diff options
Diffstat (limited to 'src/micropeak/ao_async.c')
| -rw-r--r-- | src/micropeak/ao_async.c | 43 |
1 files changed, 37 insertions, 6 deletions
diff --git a/src/micropeak/ao_async.c b/src/micropeak/ao_async.c index 04bba9e8..3556f54c 100644 --- a/src/micropeak/ao_async.c +++ b/src/micropeak/ao_async.c @@ -21,20 +21,51 @@ #define AO_ASYNC_BAUD 38400l #define AO_ASYNC_DELAY (uint8_t) (1000000l / AO_ASYNC_BAUD) +#define LED_PORT PORTB + +void +ao_async_start(void) +{ + LED_PORT |= (1 << AO_LED_SERIAL); +} + +void +ao_async_stop(void) +{ + LED_PORT &= ~(1 << AO_LED_SERIAL); +} + void ao_async_byte(uint8_t byte) { uint8_t b; uint16_t w; - /* start bit */ - - /* start data stop */ - w = 0x001 | (byte << 1) | 0x000; + /* start data stop */ + w = (0x000 << 0) | (byte << 1) | (0x001 << 9); + ao_arch_block_interrupts(); for (b = 0; b < 10; b++) { - ao_led_set((w & 1) << AO_LED_SERIAL); + uint8_t v = LED_PORT & ~(1 << AO_LED_SERIAL); + v |= (w & 1) << AO_LED_SERIAL; + LED_PORT = v; w >>= 1; - ao_delay_us(26); + + /* Carefully timed to hit around 9600 baud */ + asm volatile ("nop"); + asm volatile ("nop"); + + asm volatile ("nop"); + asm volatile ("nop"); + asm volatile ("nop"); + asm volatile ("nop"); + asm volatile ("nop"); + + asm volatile ("nop"); + asm volatile ("nop"); + asm volatile ("nop"); + asm volatile ("nop"); + asm volatile ("nop"); } + ao_arch_release_interrupts(); } |