diff --git a/nametag8_CH592/Ld/Link.ld b/nametag8_CH592/Ld/Link.ld
index 7c2899c..9ad25f2 100644
--- a/nametag8_CH592/Ld/Link.ld
+++ b/nametag8_CH592/Ld/Link.ld
@@ -152,6 +152,9 @@ SECTIONS
     	*(.srodata.cst2)
     	*(.srodata .srodata.*)
     	. = ALIGN(4);
+    	*(.ramfunc)
+  		*(.ramfunc*)
+  		. = ALIGN(4);
 		PROVIDE( _edata = .);
 	} >RAM AT>FLASH
 
diff --git a/nametag8_CH592/user/comm/soft_i2c_master.c b/nametag8_CH592/user/comm/soft_i2c_master.c
index 3476518..08cf317 100644
--- a/nametag8_CH592/user/comm/soft_i2c_master.c
+++ b/nametag8_CH592/user/comm/soft_i2c_master.c
@@ -1,30 +1,41 @@
 /*
  * soft_i2c.c
  *
- * looked at random code and fixed it up for CH59x.
+ * looked at random i2c code, used as inspiration, and wrote some
+ * garbage for CH59x.
  *
  * i2c hardware peripheral on CH59x is shared with debug pins.
- * also, i2c on CH59x is not attached to DMA. while using the
- * peripheral would result in higher speeds and less power usage,
- * living without debug is worse. maybe I'll use hw i2c later.
+ * i2c hw is also not attached to DMA. while using the peripheral
+ * even in interrupt mode would result in higher speeds and less
+ * power consumption, living without debug is worse.
  *
  * quirks and features:
  * - this implementation is blocking.
- * - partial clock stretching is supported
- *   (only during start of write, and within read phase).
- * - timings likely haven't been tested so long as this message exists.
+ * - clock stretching is supported, and somewhat tested
+ *
+ * known good settings:
+ * CYCLES_TO_HI = 5, CYCLES_TO_LOW = 2: ~400-500kHz
+ * CYCLES_TO_HI = 2, CYCLES_TO_LOW = 0: ~650KHz
  */
 
 #include <CH59x_common.h>
 #include <stdint.h>
 
 
-#define CYCLES_TO_HI    5   // these settings will result in ~500KHz (32MHz HCLK)
-#define CYCLES_TO_LO    2
+#define CYCLES_TO_HI    2
+#define CYCLES_TO_LO    0
 
-#define CYCLES_RD       2   // cycles spent in read routine
-#define CYCLES_WR_HI    2   // extra cycles spent in write routine
-#define CYCLES_WR_LO    4
+//#define CYCLES_RD       2   // cycles spent in read routine
+//#define CYCLES_WR_HI    2   // extra cycles spent in write routine
+//#define CYCLES_WR_LO    4
+
+#define bit_delay_hi()      { spin = delay_hi; while(spin--); }
+#define bit_delay_lo()      { spin = delay_lo; while(spin--); }
+
+#define rd_delay()          bit_delay_hi()
+
+#define wr_delay_hi()       bit_delay_hi()
+#define wr_delay_lo()       bit_delay_hi()      // spin = delay_hi - CYCLES_EXTRA_WR_HI; while(spin--)
 
 
 #define SDA_PIN         4
@@ -59,14 +70,6 @@ static uint16_t delay_hi, delay_lo;
 
 static volatile uint16_t spin;
 
-#define bit_delay_hi()      spin = delay_hi; while(spin--)
-#define bit_delay_lo()      spin = delay_lo; while(spin--)
-
-#define rd_delay()          bit_delay_hi()
-
-#define wr_delay_hi()       bit_delay_hi()
-#define wr_delay_lo()       bit_delay_hi()      // spin = delay_hi - CYCLES_EXTRA_WR_HI; while(spin--)
-
 
 
 // re-run init any time the clock speed changes to recalculate delays.
@@ -104,6 +107,7 @@ void i2cm_restart()
 {
     SDA_IN_HI(); bit_delay_hi();
     SCL_IN_HI();
+    while (!SCL_GET());     // clock stretch
     i2cm_start();
 }
 
@@ -124,7 +128,8 @@ void i2cm_stop()
 __attribute__((section(".ramfunc")))
 uint8_t i2cm_rd(uint8_t ack)
 {
-    uint8_t x, in = 0;
+    int8_t x;
+    uint8_t in = 0;
 
     SDA_IN_HI();
 
@@ -138,15 +143,13 @@ uint8_t i2cm_rd(uint8_t ack)
 
         if (SDA_GET()) in |= 1;
 
-        SCL_OUTLO();
+        SCL_OUTLO(); bit_delay_lo();
     }
 
     if (ack) { SDA_OUTLO(); }   // ack
     else     { SDA_IN_HI(); }   // nack
 
     SCL_IN_HI(); bit_delay_hi();
-
-    SDA_IN_HI();
     SCL_OUTLO(); bit_delay_lo();
 
     return in;
@@ -156,7 +159,7 @@ uint8_t i2cm_rd(uint8_t ack)
 __attribute__((section(".ramfunc")))
 uint8_t i2cm_wr(uint8_t dat)
 {
-    uint8_t x;
+    int8_t x;
     uint8_t ack;
 
     SCL_OUTLO();
@@ -165,8 +168,9 @@ uint8_t i2cm_wr(uint8_t dat)
         if (dat & 0x80) { SDA_IN_HI(); }
         else            { SDA_OUTLO(); }
 
-        SCL_IN_HI(); wr_delay_hi();
+        SCL_IN_HI();
         while (!SCL_GET());     // clock stretch
+        wr_delay_hi();
 
         dat <<= 1;
 
@@ -179,6 +183,7 @@ uint8_t i2cm_wr(uint8_t dat)
     ack = SDA_GET();
 
     SCL_OUTLO(); bit_delay_lo();
+
     return ack;
 }
 
@@ -186,7 +191,7 @@ uint8_t i2cm_wr(uint8_t dat)
 __attribute__((section(".ramfunc")))
 uint8_t i2cm_addr(uint8_t addr, uint8_t reading_bit)
 {
-    addr &= ~0x1;
+    addr &= 0xfe;
     addr |= reading_bit ? 1 : 0;
     return i2cm_wr(addr);
 }
diff --git a/nametag8_CH592/user/global.h b/nametag8_CH592/user/global.h
index 873c2a8..a543405 100644
--- a/nametag8_CH592/user/global.h
+++ b/nametag8_CH592/user/global.h
@@ -12,15 +12,16 @@
 
 
 
-#define SYSCLK_FREQ_NORMAL      CLK_SOURCE_HSE_16MHz
+#define SYSCLK_FREQ_NORMAL      CLK_SOURCE_PLL_48MHz    // CLK_SOURCE_HSE_16MHz
 #define SYSCLK_FREQ_USEI2C      CLK_SOURCE_PLL_32MHz
+#define SYSCLK_FREQ_IDLE        CLK_SOURCE_HSE_8MHz
 
 
 
 extern const uint8_t vers[];
 
-extern uint8_t cpu_use;
-extern uint8_t cpu_max;
+extern uint16_t cpu_pct;
+extern uint16_t cpu_pct_max;
 
 extern uint32_t uptime;
 extern uint16_t uptime_hour;
diff --git a/nametag8_CH592/user/hw/aw20xxx.c b/nametag8_CH592/user/hw/aw20xxx.c
index 7c1e39f..213a8f7 100644
--- a/nametag8_CH592/user/hw/aw20xxx.c
+++ b/nametag8_CH592/user/hw/aw20xxx.c
@@ -68,11 +68,7 @@ void aw20x_init(struct AW20x *aw, uint8_t addr, uint8_t cols, uint8_t rows, uint
     aw->rows   = rows;
     aw->config = imax & AW20X_CONF_IMAX_MASK;
 
-    // ensure we are on page 0 to start
-    aw20x_page(aw, 0);
-    while (AW20X_I2C_busy());
-
-    // wake up
+    // wake up (and set page to config page)
     aw20x_sleep(aw, 0);
 
     // enabled columns
@@ -184,9 +180,10 @@ void aw20x_led_on(struct AW20x *aw, uint8_t first, uint8_t last, uint8_t on_bit)
 }
 /*
  * enables LEDs based on user LED count, zero-indexed
- * AW20036 would be 0-35, AW00054 would be 0-53, and so on
- * for example, LEDs 8-12 on AW20054 would enable C0R8, C1R0, C1R1, C1R2
- * all other LEDs are disabled
+ * assumes AW20X_MAX_LEDON_BITS per row but will only turn on active defined rows
+ * AW20036 would be 0-35, but AW20054 would be 0-71 and so on
+ * for example, LEDs 8-12 on AW20054 with 9 roww enabled
+ * would enable C0R8, C1R0, C1R1, C1R2. all other LEDs are disabled
  *
  * todo:
  * - read current state, and apply bitfields to the currently active state
@@ -196,7 +193,7 @@ void aw20x_led_on(struct AW20x *aw, uint8_t first, uint8_t last, uint8_t on_bit)
 void aw20x_led_enable_range(struct AW20x *aw, uint8_t first, uint8_t last)
 {
     uint8_t c, r;
-    uint8_t offset = 0;
+    uint8_t idx;
     uint8_t boff;
     uint8_t *buf;
 
@@ -208,24 +205,25 @@ void aw20x_led_enable_range(struct AW20x *aw, uint8_t first, uint8_t last)
     // bits are stored 6 bits per byte, 2 bytes per column, one bit for each row
     // for a maximum of the AW20X_MAX_ROWS of LED on bits
     // we only want to touch bits that exist on the chip and in the correct order
+    idx = 0;
     for (c = 0; c < aw->cols; c++) {
         buf = &aw_buf[c*2];
+        buf[0] = buf[1] = 0;
         boff = 0;
         for (r = 0; r < AW20X_MAX_LEDON_BITS*2; r++) {
-            if (r >= aw->rows) break;               // max bits to process
+            if (r + idx < first) continue;          // only start at the first led
+            if (r + idx > last) break;              // and stop at the last
+
+            if (r >= aw->rows) continue;            // max bits to process per row
+
             if (r == AW20X_MAX_LEDON_BITS) {        // only this many bits per byte
                 boff += AW20X_MAX_LEDON_BITS;
                 buf++;
             }
 
-            if (r+offset >= first) {
-                if (r+offset <= last) {
-                    *buf |= (1 << r - boff);
-                }
-            }
+            *buf |= (1 << r - boff);
         }
-
-        offset += aw->rows;
+        idx += AW20X_MAX_LEDON_BITS*2;
     }
 
     AW20X_I2C_writereg(aw->addr, AW20X_REG_LEDON0, aw_buf, c*2);
diff --git a/nametag8_CH592/user/hw/ch32sub.c b/nametag8_CH592/user/hw/ch32sub.c
index a97b7c3..c74f731 100644
--- a/nametag8_CH592/user/hw/ch32sub.c
+++ b/nametag8_CH592/user/hw/ch32sub.c
@@ -19,9 +19,9 @@
 
 
 
-volatile uint8_t intr_flag = 0;
+volatile uint8_t intr_pending = 0;
 
-static void (*flag_cb[8])() = {
+static void (*intr_cb[8])() = {
         btn_intr,
         0,
         0,
@@ -34,38 +34,71 @@ static void (*flag_cb[8])() = {
 
 
 
+__HIGH_CODE
+void ch32sub_read(uint16_t reg, uint8_t *dat, uint8_t len)
+{
+    i2c_read_reg16(SUB_I2C_ADDR, reg, dat, len);
+}
+
+__HIGH_CODE
+void ch32sub_write(uint16_t reg, uint8_t *dat, uint8_t len)
+{
+    i2c_write_reg16(SUB_I2C_ADDR, reg, dat, len);
+}
+
+__HIGH_CODE
+uint8_t ch32sub_read_1b(uint16_t reg)
+{
+    uint8_t ret;
+
+    ch32sub_read(reg, &ret, 1);
+
+    return ret;
+}
+
+__HIGH_CODE
+void ch32sub_write_1b(uint16_t reg, uint8_t dat)
+{
+    i2c_addr(SUB_I2C_ADDR, 0);
+    i2c_wr(reg >> 8);
+    i2c_wr(reg & 0xff);
+    i2c_wr(dat);
+    i2c_stop();
+}
+
 void ch32sub_isr()
 {
-    // we'll check what the MCU has to say when we're done processing
-    intr_flag = 1;
+    intr_pending = 1;
 }
 
 void ch32sub_process()
 {
     uint8_t flags;
+    uint8_t clear = 0;
     uint8_t i;
 
-    if (intr_flag) {
-        intr_flag = 0;
-        flags = 1;
+    if (intr_pending) {
+        intr_pending = 0;
 
-        // get interrupt flags
-        i2c_read_reg16(SUB_I2C_ADDR, REG_INTR_FLAGS, &flags, 1);
+        // get flags
+        flags = ch32sub_read_1b(REG_INTR_FLAGS);
 
-        while (flags) {
-            for (i = 0; i < 8; i++) {
-                if (intr_flag & (1 << i)) {
-                    if (flag_cb[i]) flag_cb[i]();
-                    else {
-                        // unhandled interrupt; clear it
-                        // ch32sub_write_1b(REG_INTR_FLAGS, i << 1);
-                    }
+        // process flags
+        for (i = 0; i < 8; i++) {
+            if (flags & (1 << i)) {
+                if (intr_cb[i]) {
+                    clear |= (i << 1);
+                    intr_cb[i]();
+                }
+                else {
+                    // unhandled interrupt; clear it?
+                    // ch32sub_write_1b(REG_INTR_FLAGS, i << 1);
                 }
             }
-
-            // get interrupt flags (again)
-            i2c_read_reg16(SUB_I2C_ADDR, REG_INTR_FLAGS, &flags, 1);
         }
+
+        // clear flags
+        ch32sub_write_1b(REG_INTR_FLAGS_CLEAR, clear);
     }
 }
 
@@ -81,31 +114,29 @@ void ch32sub_init()
     // note: this is handled as "high priority" within the interrupt handler now.
     // port_intr_cb_register(PORT_INTR_GPIOB, SUB_INTR_PIN_NR, ch32sub_isr);
 
-
-}
-
-// things to do
-void ch32sub_read(uint16_t reg, uint8_t *dat, uint8_t len)
-{
-    i2c_read_reg16(SUB_I2C_ADDR, reg, dat, len);
-}
-
-void ch32sub_write(uint16_t reg, uint8_t *dat, uint8_t len)
-{
-    i2c_write_reg16(SUB_I2C_ADDR, reg, dat, len);
-}
-
-void ch32sub_write_1b(uint16_t reg, uint8_t dat)
-{
-    i2c_start();
-    i2c_addr(SUB_I2C_ADDR, 0);
-    i2c_wr(reg >> 8);
-    i2c_wr(reg & 0xff);
-    i2c_wr(dat);
-    i2c_stop();
+    // clear any interrupts now, to start from clean slate
+    ch32sub_write_1b(REG_INTR_FLAGS_CLEAR, 0xff);
 }
 
 void ch32sub_rgb_hwen(uint8_t en)
 {
     ch32sub_write_1b(REG_RGB_HWEN, en);
 }
+
+void ch32sub_intr_defaults()
+{
+    int8_t i;
+    uint8_t dat[5];
+
+    // we want interrupted for all button events
+    for (i = 0; i < 5; i++) {
+        dat[i] = BTN_PUSH | BTN_HOLD | BTN_RELEASE;
+    }
+
+    // enable button interrupt sources
+    ch32sub_write(REG_BTN1_INT_ENABLE, dat, 5);
+
+    // enable all interrupt flags we care about
+    dat[0] = INT_BTN | INT_UTX_DONE | INT_UTX_TIMEOUT | INT_UTX_ERROR | INT_URX_RCVD;
+    ch32sub_write_1b(REG_INTR_ENABLE, dat[0]);
+}
diff --git a/nametag8_CH592/user/hw/ch32sub.h b/nametag8_CH592/user/hw/ch32sub.h
index cd0bd32..da532d2 100644
--- a/nametag8_CH592/user/hw/ch32sub.h
+++ b/nametag8_CH592/user/hw/ch32sub.h
@@ -97,6 +97,12 @@ enum ch32sub_regmap {
 };
 
 
+#define BTN_PUSH        (1 << 0)
+#define BTN_HOLD        (1 << 1)
+#define BTN_RELEASE     (1 << 2)
+#define BTN_IGNORE      (1 << 3)
+
+
 
 void ch32sub_init();
 void ch32sub_isr();
@@ -106,6 +112,7 @@ void ch32sub_read(uint16_t reg, uint8_t *dat, uint8_t len);
 void ch32sub_write(uint16_t reg, uint8_t *dat, uint8_t len);
 void ch32sub_write_1b(uint16_t reg, uint8_t dat);
 
+void ch32sub_intr_defaults();
 void ch32sub_rgb_hwen(uint8_t en);
 
 
diff --git a/nametag8_CH592/user/hw/eeprom16.c b/nametag8_CH592/user/hw/eeprom16.c
index d8c906f..0d3e1b0 100644
--- a/nametag8_CH592/user/hw/eeprom16.c
+++ b/nametag8_CH592/user/hw/eeprom16.c
@@ -19,14 +19,13 @@ void e16_read(uint16_t addr, uint8_t *dat, uint32_t len)
 {
     if (len > EEPROM_SIZE) return;
 
-    i2c_start();
     i2c_addr(EEPROM_I2C_ADDR, 0);
     i2c_wr(addr >> 8);
     i2c_wr(addr & 0xff);
     i2c_restart();
-    i2c_addr(EEPROM_I2C_ADDR, 1);
+    i2c_wr(EEPROM_I2C_ADDR | 1);
 
-    while (len--) *dat++ = i2cm_rd(len > 0);
+    while (len--) *dat++ = i2c_rd(len > 0);
 
     i2c_stop();
 }
@@ -42,15 +41,16 @@ void e16_write(uint16_t addr, uint8_t *dat, uint16_t len)
     // it is your responsibility to correctly address for
     // page boundaries. most eeprom roll over page boundaries.
 
-    i2c_start();
     i2c_addr(EEPROM_I2C_ADDR, 0);
     i2c_wr(addr >> 8);
     i2c_wr(addr & 0xff);
 
     while  (len--) {
-        nack = i2cm_wr(*dat++);
+        nack = i2c_wr(*dat++);
         if (nack) break;
     }
+
+    i2c_stop();
 }
 
 
diff --git a/nametag8_CH592/user/hw/gat/gat_gpio.c b/nametag8_CH592/user/hw/gat/gat_gpio.c
index 5c2c767..16edce9 100644
--- a/nametag8_CH592/user/hw/gat/gat_gpio.c
+++ b/nametag8_CH592/user/hw/gat/gat_gpio.c
@@ -8,6 +8,11 @@
  * - GP1 has UART0 TX and PWM9.
  * - GP2 has UART0 RX and PWM7.
  *
+ * errata:
+ * - bottom board marked REV3 has addon header mirrored.
+ *   to manufacture this, GAT GPIO is cut and inoperable.
+ *   todo: add strapping GPIO check to determine board version.
+ *
  */
 
 
diff --git a/nametag8_CH592/user/led/rgbled.c b/nametag8_CH592/user/led/rgbled.c
index 65d0420..7bf1d92 100644
--- a/nametag8_CH592/user/led/rgbled.c
+++ b/nametag8_CH592/user/led/rgbled.c
@@ -61,10 +61,11 @@ void rgbled_init()
 {
     volatile uint32_t x;
 
-    ch32sub_rgb_hwen(1);
+    // make sure the hardware pin is on before calling.
+
 
     // wait a little while to ensure controller is awake
-    x = GetSysClock() / 16384;
+    x = GetSysClock() / 131072;
     while (x--);
 
     // clear fade
@@ -76,7 +77,7 @@ void rgbled_init()
 
     aw20x_set_dim_global(&awled, AW20X_DIM);
     aw20x_set_fade(&awled);
-    aw20x_led_enable_range(&awled, 0, 23);
+    aw20x_led_enable_range(&awled, 0, 47);  // 9x4, but need to send 12x4
 }
 
 void rgbled_flag_update()
@@ -104,8 +105,14 @@ void rgbled_send()
 
 void rgbled_runprog(uint8_t tick_ctr)
 {
+    uint8_t idx = uconf.ledprog_rgb_idx;
+
     // run program
-    if (rgb_pgm[uconf.ledprog_rgb_idx].prog) {
-        rgb_pgm[uconf.ledprog_rgb_idx].prog(uconf.ledprog_rgb_data[uconf.ledprog_rgb_idx], tick_ctr);
+    if (rgb_pgm[idx].prog) {
+        // render
+        rgb_pgm[idx].prog(uconf.ledprog_rgb_data[uconf.ledprog_rgb_idx], tick_ctr);
+
+        // and for now, always force an update
+        led_matrix_needs_update = 1;
     }
 }
diff --git a/nametag8_CH592/user/main.c b/nametag8_CH592/user/main.c
index f5cfbb6..9cd2389 100644
--- a/nametag8_CH592/user/main.c
+++ b/nametag8_CH592/user/main.c
@@ -43,20 +43,25 @@
 
 
 // global settings
-#define OLED_UPDATE_RATE        8      // framerate of OLED; (256*(6/8)) / OLED_UPDATE_RATE; 8 = 24FPS
+#define OLED_UPDATE_RATE        13      // framerate of OLED; { (256*(8/8)) / OLED_UPDATE_RATE }; 13 = 19FPS
 
 // flags
 #define FLAG_OLED_UPDATE        (1 << 0)
 #define FLAG_RGBLED_RUN_PROG    (1 << 1)
+#define FLAG_PROG_TICK_INTR     (1 << 7)
 
-#define PROG_TICK_RATE          (32768 / 256)
+#define FLAG_RESET_SYSTICK      (1 << 6)
+
+#define PROG_TICK_RATE          ((32768 / 256) - 1)
 
 
 
 const uint8_t vers[] = "241015a";
 
-uint8_t cpu_use = 0;
-uint8_t cpu_max = 0;
+uint32_t cpu_use = 0;
+uint32_t cpu_max = 0;
+uint16_t cpu_pct = 0;
+uint16_t cpu_pct_max = 0;
 
 uint32_t uptime = 0;
 uint16_t uptime_hour;
@@ -67,9 +72,10 @@ uint32_t idle_time_menu;
 uint32_t idle_time_still;
 uint8_t  idle_go_sleep;
 
-static volatile uint8_t flags = 0;
+static volatile uint8_t flags_lo = 0;
+static uint8_t flags_hi = FLAG_RESET_SYSTICK;
 
-static uint8_t st_tick = 0;             // systick loop counter
+static uint8_t st_tick = 0;             // program tick counter
 static uint8_t oled_tick = 0;           // oled framerate counter
 
 
@@ -107,17 +113,22 @@ void rtc_reset_trig()
 
 void rtcisr_init()
 {
-    LClk32K_Cfg(Clk32K_LSI, ENABLE);                // enable internal oscillator
-    Calibration_LSI(Level_128);                     // calibrate LSI fromm HSE
+    LClk32K_Cfg(Clk32K_LSI, ENABLE);        // enable internal oscillator
+    Calibration_LSI(Level_128);             // calibrate LSI fromm HSE
 
     rtc_reset_trig();
     PFIC_EnableIRQ(RTC_IRQn);
 }
 
+void systick_init(void)
+{
+    SysTick->CNT = 0;                                       // clear counter
+    SysTick->CTLR = SysTick_CTLR_STCLK | SysTick_CTLR_STE;  // enable counter in /1 mode
+}
+
 __HIGH_CODE
 void oled_update_done()
 {
-    int16_t a;
     int8_t rot;
 
     // reset oled callback, clear screen, and set default pixel mode and font size
@@ -153,6 +164,7 @@ void oled_update_done()
 
 #ifdef MENU_TIMEOUT_TO_NAMETAG
     // root menu idle counting
+    // note: untested.
     if (menu == &menu_0) {
         if (!idle_time_menu) {
             idle_time_menu = uptime;
@@ -167,87 +179,37 @@ void oled_update_done()
     }
 #endif
 
-    // do menu operations
+    // render menu
     menu_tick();
 
     // calculate CPU usage
-    // note: we just consider missed ticks a percent.
-    // it's actually more like a tenth. fuck it.
-    // a = missed;
-    // todo: implement this
-    a = 0;
-
-    if (uconf.framemod == UCONF_FRAMERATE_HALF) {
-        // the above calculation is tied to framerate.
-        // so this will compensate for half framerate mode...
-        a >>= 1;
-    }
-
-    if (a > cpu_max) {
-        cpu_max = a;
-    }
-    cpu_use = a;
-
-
-    // reset missed interrupt counter
-    // missed = 0;
+    cpu_pct = (cpu_use * 100) / cpu_max;
+    if (cpu_pct > cpu_pct_max) cpu_pct_max = cpu_pct;
 }
 
 
+__HIGH_CODE
+void lowprio_task() {
+    uint32_t interrupt_flags;
 
-int main()
-{
-    // configure clock
-    ch59x_xtal_conf();
-    SetSysClock(SYSCLK_FREQ_USEI2C);
-    // note that system clock speed is decreased after every use of I2C.
-
-    // enable DC-DC converter; brings significant power saving
-    PWR_DCDCCfg(ENABLE);
-
-    // get i2c initialized since most stuff will need it
-    i2c_init();
-
-    // read the user config
-    uconf_load();
-
-    // initialize aux MCU
-    ch32sub_init();
-    // and enable RGBLED controller hardware pin so the controller can wake up
-    ch32sub_rgb_hwen(1);
-
-    // initialize accelerometer
-    accel_init();
-
-    // initialize RGBLED controller
-    rgbled_init();
-
-    // configure GAT aux GPIOs, get gat ID
-    gat_gpio_init();
-    // configure GAT i2c slave
-    // not yet implemented
-
-    // configure port-based interrupts (used for ch32sub interrupt)
-    port_intr_init();
-
-    // start up the OLED and menu system
-    ssd1306fb_set_target(&oled);
-    ssd1306_init(1);    // we'll try to init later too, since sometimes they fail
-    menu_stop(0);       // lol. yes, this "starts" the "menu" in nametag mode
-
-    // configure main program tick interrupt
-    rtcisr_init();
-
-    while(1) {
+    while (1) {
         // sleep when we're doing nothing
-        __WFI();
+        if (!flags_lo) {
+            __WFI();
+        }
 
-        // only care about aux MCU when all other processing is done
+        // disable all IRQs when doing any I2C related stuff, as interrupts
+        // can corrupt transactions
+        SYS_DisableAllIrq(&interrupt_flags);
+
+        // temporary: enable sub interrupts
+        ch32sub_intr_defaults();
+        // process sub MCU interrupt, if pending
         ch32sub_process();
 
         // send the last oled frame data
-        if (flags & FLAG_OLED_UPDATE) {
-            flags &= ~FLAG_OLED_UPDATE;
+        if (flags_lo & FLAG_OLED_UPDATE) {
+            flags_lo &= ~FLAG_OLED_UPDATE;
 
             /*** oled ***/
             if (oled.callback && !(oled.state & SSD1306_STATE_BUSY)) {
@@ -267,24 +229,90 @@ int main()
             }
         }
 
-        // render new OLED frame
-        if (flags & FLAG_RGBLED_RUN_PROG) {
-            flags &= ~FLAG_RGBLED_RUN_PROG;
+        // send the RGBLED data
+        // todo
+
+        // capture CPU use
+        if (flags_lo & FLAG_PROG_TICK_INTR) {
+            flags_lo &= ~FLAG_PROG_TICK_INTR;
+            flags_hi |= FLAG_RESET_SYSTICK;
+            cpu_use = SysTick->CNT;
+        }
+
+        // re-enable IRQs
+        SYS_RecoverIrq(interrupt_flags);
+
+        // render new rgbled frame
+        if (flags_lo & FLAG_RGBLED_RUN_PROG) {
+            flags_lo &= ~FLAG_RGBLED_RUN_PROG;
             rgbled_runprog(st_tick);
         }
+
+        // drop into lower clock rate
+        SetSysClock(SYSCLK_FREQ_IDLE);
     }
 }
 
 
+int main()
+{
+    // configure clock
+    ch59x_xtal_conf();
+    SetSysClock(SYSCLK_FREQ_USEI2C);
+    // note that system clock speed is decreased after every use of I2C.
+
+    PWR_DCDCCfg(ENABLE);            // enable DC-DC converter; brings significant power saving
+
+    i2c_init();                     // get i2c initialized since most stuff will need it
+
+    uconf_load();                   // read the user config
+
+    ch32sub_init();                 // initialize aux MCU
+    ch32sub_rgb_hwen(1);            // and enable RGBLED controller hardware pin so the controller can wake up
+
+    accel_init();                   // initialize accelerometer
+    rgbled_init();                  // initialize RGBLED controller
+
+    gat_gpio_init();                // configure GAT aux GPIOs, get gat ID
+    // todo: implement              // configure GAT i2c slave
+
+    ssd1306fb_set_target(&oled);    // start up the OLED and menu system
+    ssd1306_init(1);                // we'll try to init later too, since sometimes OLED fails to init
+    menu_stop(0);                   // lol. yes, this "starts" the "menu" in nametag mode
+
+    systick_init();                 // start up the system tick, used for CPU percentage calculation
+    cpu_max = GetSysClock() / PROG_TICK_RATE;
+
+    port_intr_init();               // configure port-based interrupts (used for ch32sub interrupt)
+    ch32sub_intr_defaults();        // configure interrupt sources on sub MCU - buttons, etc
+
+    // configure main program tick interrupt
+    rtcisr_init();
+
+    // start the low priority task loop
+    lowprio_task();
+}
+
+
 __INTERRUPT
 __HIGH_CODE
 void RTC_IRQHandler(void)
 {
+    // clear systick for CPU usage counting
+    if (flags_hi & FLAG_RESET_SYSTICK) {
+        SysTick->CNT = 0;
+        flags_hi &= ~FLAG_RESET_SYSTICK;
+        flags_lo |=  FLAG_PROG_TICK_INTR;
+    }
+
+    // speed up
+    SetSysClock(SYSCLK_FREQ_NORMAL);
+
     // clear interrupt flag and reset RTC
     rtc_reset_trig();
 
+    // manual uptime counter
     st_tick++;
-
     if (!st_tick) {
         uptime++;
         uptime_hour = (uint16_t)(uptime / 3600);
@@ -305,24 +333,18 @@ void RTC_IRQHandler(void)
             rgbled_send();
 
             // defer rendering
-            flags |= FLAG_RGBLED_RUN_PROG;
+            flags_lo |= FLAG_RGBLED_RUN_PROG;
             break;
         }
         case 1: {
             accel_poll();
             // no break
         }
-        default: {
-            oled_tick++;
-            if (oled_tick >= OLED_UPDATE_RATE) {
-                oled_tick = 0;
-                flags |= FLAG_OLED_UPDATE;
-            }
-        }
     }
 
-    // read accelerometer data at 32Hz
-    if ((st_tick & 0x7) == 0x7) {
-
+    oled_tick++;
+    if (oled_tick >= OLED_UPDATE_RATE) {
+        oled_tick = 0;
+        flags_lo |= FLAG_OLED_UPDATE;
     }
 }
diff --git a/nametag8_CH592/user/misc/accel.c b/nametag8_CH592/user/misc/accel.c
index 501991e..cf26449 100644
--- a/nametag8_CH592/user/misc/accel.c
+++ b/nametag8_CH592/user/misc/accel.c
@@ -33,7 +33,7 @@ int32_t accel_i2c_write(void *handle, uint8_t reg, const uint8_t *bufp, uint16_t
 {
     (void)(handle);
 
-    i2c_write_reg8(LIS2DW_I2C_ADDR, reg, bufp, len);
+    i2c_write_reg8(LIS2DW_I2C_ADDR_SDO_LOW, reg, bufp, len);
 
     return 0;
 }
@@ -42,7 +42,7 @@ int32_t accel_i2c_read(void *handle, uint8_t reg, uint8_t *bufp, uint16_t len)
 {
     (void)(handle);
 
-    i2c_read_reg8(LIS2DW_I2C_ADDR, reg, bufp, len);
+    i2c_read_reg8(LIS2DW_I2C_ADDR_SDO_LOW, reg, bufp, len);
 
     return 0;
 }
@@ -72,7 +72,7 @@ void accel_init()
                 timeout = 0;
                 accel_found = 1;
             }
-        } while (timeout);
+        } while (timeout--);
     }
 
     if (accel_found) {
@@ -98,7 +98,7 @@ void accel_init()
 void accel_poll()
 {
     uint8_t reg = 1;
-    uint16_t xyz[3];
+    int16_t xyz[3];
 
     if (!accel_found) return;
 
@@ -110,6 +110,9 @@ void accel_poll()
             // read acceleration data
             memset(xyz, 0x00, 3 * sizeof(int16_t));
             lis2dw12_acceleration_raw_get(&dev_ctx, xyz);
+            accel.x = xyz[0] >>= 8;
+            accel.y = xyz[1] >>= 8;
+            accel.z = xyz[2] >>= 8;
         }
     }
 }
diff --git a/nametag8_CH592/user/misc/tinymt.c b/nametag8_CH592/user/misc/tinymt.c
index ca1937d..3322b82 100644
--- a/nametag8_CH592/user/misc/tinymt.c
+++ b/nametag8_CH592/user/misc/tinymt.c
@@ -7,6 +7,8 @@
 #include <stdint.h>
 #include "tinymt.h"
 
+#include "CH59x_common.h"
+
 
 
 static void tinymt32_next_state(tinymt32_t *s);
@@ -91,7 +93,8 @@ const uint32_t  TINYMT32_MASK = UINT32_C(0x7fffffff);
  * This function changes the internal state of tinymt32.
  * @param s     pointer to tinymt internal state.
  */
-static void tinymt32_next_state (tinymt32_t* s)
+__HIGH_CODE
+void tinymt32_next_state (tinymt32_t* s)
 {
     uint32_t x;
     uint32_t y;
@@ -128,7 +131,8 @@ static void tinymt32_next_state (tinymt32_t* s)
  * @param s     pointer to tinymt internal state.
  * @return      32-bit unsigned pseudorandom number.
  */
-static uint32_t tinymt32_temper (tinymt32_t* s)
+__HIGH_CODE
+uint32_t tinymt32_temper (tinymt32_t* s)
 {
     uint32_t t0, t1;
     t0 = s->status[3];
diff --git a/nametag8_CH592/user/port_intr.c b/nametag8_CH592/user/port_intr.c
index 61eaf78..081c9de 100644
--- a/nametag8_CH592/user/port_intr.c
+++ b/nametag8_CH592/user/port_intr.c
@@ -43,7 +43,9 @@ void port_intr_cb_register(uint8_t port, uint8_t idx, void (*fn)(void))
 
 void port_intr_init()
 {
-    // enable port interrupt
+    // clear state then enable port interrupt
+    R16_PB_INT_IF = 0xff;
+    PFIC_EnableIRQ(GPIO_B_IRQn);
 }
 
 
@@ -63,8 +65,8 @@ __INTERRUPT
 __HIGH_CODE
 void GPIOB_IRQHandler(void)
 {
-    uint8_t i;
-    uint8_t offset;
+    //uint8_t i;
+    //uint8_t offset;
     uint16_t flag = R16_PB_INT_IF;
 
     // clear flags
@@ -77,6 +79,7 @@ void GPIOB_IRQHandler(void)
     }
 
     // general purpose fallback
+    /*
     for (i = 4; i < MAX_PIN; i++) {
         offset = i - 4;
         if (flag & (1 << i)) {
@@ -85,4 +88,5 @@ void GPIOB_IRQHandler(void)
             }
         }
     }
+    */
 }
diff --git a/nametag8_CH592/user/ui/btn.c b/nametag8_CH592/user/ui/btn.c
index 13aebaf..9dff031 100644
--- a/nametag8_CH592/user/ui/btn.c
+++ b/nametag8_CH592/user/ui/btn.c
@@ -21,18 +21,21 @@ uint8_t btn_held;
 
 
 
+__HIGH_CODE
 void btn_push_cb(uint8_t idx)
 {
     btn_pushed |= (1 << idx);
     if (btn[idx].cb_push) btn[idx].cb_push(idx);
 }
 
+__HIGH_CODE
 void btn_hold_cb(uint8_t idx)
 {
     btn_held |= (1 << idx);
     if (btn[idx].cb_hold) btn[idx].cb_hold(idx);
 }
 
+__HIGH_CODE
 void btn_release_cb(uint8_t idx)
 {
     btn_pushed &= ~(1 << idx);
@@ -41,6 +44,7 @@ void btn_release_cb(uint8_t idx)
 }
 
 
+__HIGH_CODE
 void btn_commit_hold()
 {
     uint8_t i, x;
@@ -66,6 +70,7 @@ void btn_commit_hold()
 }
 
 
+__HIGH_CODE
 void btn_intr()
 {
     uint8_t i;
@@ -76,7 +81,8 @@ void btn_intr()
     ch32sub_read(REG_BTN_PUSHED_LATCHED, btn_state, sizeof(btn_state));
 
     // clear button interrupt flag
-    ch32sub_write_1b(REG_INTR_FLAGS_CLEAR, INT_BTN);
+    // this is actually handled by the main routine so not needed here
+    // ch32sub_write_1b(REG_INTR_FLAGS_CLEAR, INT_BTN);
 
     // process callbacks for new events
     for (i = 0; i < BTN_COUNT; i++) {
diff --git a/nametag8_CH592/user/ui/menu_base.c b/nametag8_CH592/user/ui/menu_base.c
index c8e2c21..c3cae35 100644
--- a/nametag8_CH592/user/ui/menu_base.c
+++ b/nametag8_CH592/user/ui/menu_base.c
@@ -9,12 +9,15 @@
 #include <string.h>
 
 
+
 MenuItem *menu;
 uint8_t menu_idx = 0;
 
 uint8_t mtick;
 
 
+
+__HIGH_CODE
 void menu_tick()
 {
 	if (menu) {
@@ -149,6 +152,7 @@ void menu_btn_use_none()
 }
 
 
+__HIGH_CODE
 void menu_draw_buttons(uint8_t mode, uint8_t mask)
 {
 	uint8_t w;
@@ -274,6 +278,7 @@ void menu_draw_buttons(uint8_t mode, uint8_t mask)
 	}
 }
 
+__HIGH_CODE
 void menu_draw_tabs(uint8_t active_idx)
 {
 	uint8_t h;
diff --git a/nametag8_CH592/user/ui/menu_entry_0.c b/nametag8_CH592/user/ui/menu_entry_0.c
index 1120086..4948497 100644
--- a/nametag8_CH592/user/ui/menu_entry_0.c
+++ b/nametag8_CH592/user/ui/menu_entry_0.c
@@ -95,6 +95,7 @@ static void menu_none_print_error(uint8_t *err1, uint8_t *err2, uint8_t *err3)
 	return;
 }
 
+__HIGH_CODE
 void menu_none_disp(uint8_t idx)
 {
 	uint8_t i, j;
@@ -239,7 +240,7 @@ MENU_0_DISP_CHAR_ROTATE:
 	}
 
 	if (uconf.flags & UCONF_FLAGS_SHOW_CPU_USAGE) {
-		sprintf(txt, "%3u%%", cpu_use);
+		sprintf(txt, "%3u%%", cpu_pct);
 		ssd1306fb_set_cursor(90, 20);
 		ssd1306fb_draw_str(font_DejaVu_Sans_Mono_Bold_11, txt, 1);
 	}
@@ -247,6 +248,7 @@ MENU_0_DISP_CHAR_ROTATE:
 	oled.state &= ~SSD1306_STATE_STR_HALFWIDTH;
 }
 
+__HIGH_CODE
 void menu_0_disp(uint8_t idx)
 {
 	char txt[12];
diff --git a/nametag8_CH592/user/ui/menu_entry_1.c b/nametag8_CH592/user/ui/menu_entry_1.c
index a0483a0..e449a20 100644
--- a/nametag8_CH592/user/ui/menu_entry_1.c
+++ b/nametag8_CH592/user/ui/menu_entry_1.c
@@ -205,6 +205,7 @@ void menu_1_font_next()
 	} while (!font_table[uconf.font_idx].tag_allowed);
 }
 
+__HIGH_CODE
 void menu_1_disp(uint8_t idx)
 {
 	int8_t w, x;
diff --git a/nametag8_CH592/user/ui/menu_entry_2.c b/nametag8_CH592/user/ui/menu_entry_2.c
index 208c248..2209e3c 100644
--- a/nametag8_CH592/user/ui/menu_entry_2.c
+++ b/nametag8_CH592/user/ui/menu_entry_2.c
@@ -220,6 +220,7 @@ void menu_2_edit_use(uint8_t idx)
 }
 
 
+__HIGH_CODE
 void menu_2_disp(uint8_t idx)
 {
 	int i;
diff --git a/nametag8_CH592/user/ui/menu_entry_3.c b/nametag8_CH592/user/ui/menu_entry_3.c
index 3780012..7913c90 100644
--- a/nametag8_CH592/user/ui/menu_entry_3.c
+++ b/nametag8_CH592/user/ui/menu_entry_3.c
@@ -325,6 +325,8 @@ void snek_init()
 	gamemode = 17;
 }
 
+
+__HIGH_CODE
 void snek_disp(uint8_t idx)
 {
 	// uint8_t i;
diff --git a/nametag8_CH592/user/ui/menu_entry_5.c b/nametag8_CH592/user/ui/menu_entry_5.c
index c004556..dda7e13 100644
--- a/nametag8_CH592/user/ui/menu_entry_5.c
+++ b/nametag8_CH592/user/ui/menu_entry_5.c
@@ -27,6 +27,7 @@ const uint16_t sleep_times[] = {
 };
 
 
+__HIGH_CODE
 void menu_5_disp(uint8_t idx)
 {
 	int8_t w, x;
diff --git a/nametag8_CH592/user/ui/menu_entry_6.c b/nametag8_CH592/user/ui/menu_entry_6.c
index 2d8b990..fa05b4d 100644
--- a/nametag8_CH592/user/ui/menu_entry_6.c
+++ b/nametag8_CH592/user/ui/menu_entry_6.c
@@ -101,6 +101,7 @@ void menu_6_btn_use()
 	btn_commit_hold();
 }
 
+__HIGH_CODE
 void menu_6_disp(uint8_t idx)
 {
 	uint8_t i;
@@ -220,11 +221,11 @@ void menu_6_disp(uint8_t idx)
 			break;
 		}
 		case 5: {
-			sprintf(txt, "CPU Load: %3u%%", cpu_use);
+			sprintf(txt, "CPU Load: %3u%%", cpu_pct);
 			ssd1306fb_set_cursor(10, -1);
 			ssd1306fb_draw_str(font_DejaVu_Sans_Mono_Bold_11, txt, 1);
 
-			sprintf(txt, "CPU  Max: %3u%%", cpu_max);
+			sprintf(txt, "CPU  Max: %3u%%", cpu_pct_max);
 			ssd1306fb_set_cursor(10, 9);
 			ssd1306fb_draw_str(font_DejaVu_Sans_Mono_Bold_11, txt, 1);
 
diff --git a/nametag8_CH592/user/user_config.h b/nametag8_CH592/user/user_config.h
index e47e7a2..0561dd3 100644
--- a/nametag8_CH592/user/user_config.h
+++ b/nametag8_CH592/user/user_config.h
@@ -15,7 +15,7 @@
 
 
 // some global options
-#define FLASH_RSVD_PAGES                16          // how many FLASH_UCONF_BYTES to reserve/check
+#define FLASH_RSVD_PAGES                8           // how many FLASH_UCONF_BYTES to reserve/check
 #define FLASH_UCONF_BYTES               256         // basically assumed everywhere
 
 #define MISC_WIGGLE_RATE                (7 - 4);