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mega2560/parallel.c: return immediately when perif cycle not ready

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Jeremy Soller 2020-12-29 09:55:24 -07:00 committed by Jeremy Soller
parent f0c129c9f1
commit 932dbe8e71
1 changed files with 16 additions and 10 deletions
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26
src/board/arduino/mega2560/parallel.c
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@ -255,7 +255,7 @@ int parallel_transaction(struct Parallel * port, uint8_t * data, int length, boo
// Set data strobe high
gpio_set(port->data_n, true);
}
// Wait for peripheral to indicate it's ready for next cycle
while (gpio_get(port->wait_n)) {}
@ -290,7 +290,11 @@ bool parallel_peripheral_cycle(struct Parallel * port, uint8_t * data, bool * re
return false;
}
while (gpio_get(port->data_n) && gpio_get(port->addr_n)) {}
// Check for data or address cycle
if (gpio_get(port->data_n) && gpio_get(port->addr_n)) {
// No cycle ready
return false;
}
*read = gpio_get(port->write_n);
*addr = !gpio_get(port->addr_n);
@ -301,10 +305,11 @@ bool parallel_peripheral_cycle(struct Parallel * port, uint8_t * data, bool * re
parallel_write_data(port, *data);
}
// Tell host we are ready for cycle
gpio_set(port->wait_n, true);
// Wait for host to finish strobe
while (!gpio_get(port->addr_n) || !gpio_get(port->data_n)) {}
while (!gpio_get(port->data_n) || !gpio_get(port->addr_n)) {}
if (*read) {
// Set data lines back to inputs
@ -314,7 +319,7 @@ bool parallel_peripheral_cycle(struct Parallel * port, uint8_t * data, bool * re
*data = parallel_read_data(port);
}
// Tell host we're ready for next cycle
// Tell host we are ready for next cycle
gpio_set(port->wait_n, false);
return true;
@ -490,18 +495,19 @@ int parallel_main(void) {
// Debug console
case 'C':
// Set parallel lines to peripheral mode
parallel_state(port, PARALLEL_STATE_PERIPHERAL);
// Tell the user the console is ready
serial_write(console_msg, sizeof(console_msg));
for (;;) {
bool read = false;
bool addr = false;
bool ret = parallel_peripheral_cycle(port, data, &read, &addr);
if (ret && !read && !addr) {
res = serial_write(data, 1);
if (res < 0) goto err;
if (parallel_peripheral_cycle(port, data, &read, &addr)) {
if (!read && !addr) {
res = serial_write(data, 1);
if (res < 0) goto err;
}
}
}