diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/lcd_st7920.c | 36 |
1 files changed, 27 insertions, 9 deletions
diff --git a/src/lcd_st7920.c b/src/lcd_st7920.c index 4351d6ac..8cd76c50 100644 --- a/src/lcd_st7920.c +++ b/src/lcd_st7920.c @@ -12,7 +12,7 @@ #include "sched.h" // DECL_SHUTDOWN struct st7920 { - uint32_t last_cmd_time, cmd_wait_ticks; + uint32_t last_cmd_time, sync_wait_ticks, cmd_wait_ticks; struct gpio_out sclk, sid; }; @@ -45,16 +45,31 @@ st7920_xmit_byte(struct st7920 *s, uint8_t data) static void st7920_xmit(struct st7920 *s, uint8_t count, uint8_t *cmds) { - uint32_t last_cmd_time=s->last_cmd_time, cmd_wait_ticks=s->cmd_wait_ticks; - while (count--) { + if (!count) + return; + + // Send first byte (with longer delay) + uint32_t last_cmd_time = s->last_cmd_time, wait_ticks = s->sync_wait_ticks; + uint8_t cmd = *cmds++; + st7920_xmit_byte(s, cmd & 0xf0); + while (timer_read_time() - last_cmd_time < wait_ticks) + // Can't complete transfer until delay complete + irq_poll(); + st7920_xmit_byte(s, cmd << 4); + last_cmd_time = timer_read_time(); + + // Send subsequent bytes + wait_ticks = s->cmd_wait_ticks; + while (--count) { uint8_t cmd = *cmds++; st7920_xmit_byte(s, cmd & 0xf0); - // Can't complete transfer until delay complete - while (timer_read_time() - last_cmd_time < cmd_wait_ticks) + while (timer_read_time() - last_cmd_time < wait_ticks) + // Can't complete transfer until delay complete irq_poll(); st7920_xmit_byte(s, cmd << 4); last_cmd_time = timer_read_time(); } + s->last_cmd_time = last_cmd_time; } @@ -80,13 +95,16 @@ command_config_st7920(uint32_t *args) uint32_t end = timer_read_time(); irq_enable(); s->last_cmd_time = end; - uint32_t diff = end - start, delay_ticks = args[4]; - if (delay_ticks > diff) - s->cmd_wait_ticks = delay_ticks - diff; + uint32_t diff = end - start, sync_delay_ticks = args[4]; + if (sync_delay_ticks > diff) + s->sync_wait_ticks = sync_delay_ticks - diff; + uint32_t cmd_delay_ticks = args[5]; + if (cmd_delay_ticks > diff) + s->cmd_wait_ticks = cmd_delay_ticks - diff; } DECL_COMMAND(command_config_st7920, "config_st7920 oid=%c cs_pin=%u sclk_pin=%u sid_pin=%u" - " delay_ticks=%u"); + " sync_delay_ticks=%u cmd_delay_ticks=%u"); void command_st7920_send_cmds(uint32_t *args) |