Boyu Fang
/
biuart_test
test program for biuart
Diff: main.cpp
- Revision:
- 0:40d82aa11fe0
- Child:
- 1:36aff54b80e2
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Mon Aug 11 10:38:04 2014 +0000 @@ -0,0 +1,117 @@ +#include "mbed.h" +#include <vector> + +Serial pc(USBTX, USBRX); +Serial uart(p13, p14); +DigitalInOut nREQ(p15); +DigitalInOut nRDY(p16); + +uint16_t ccitt(uint8_t len, uint8_t* buf); + +uint16_t ccitt(uint8_t len, uint8_t* buf) { + // length is masked to 8 bits (256=0) for checksum calculation, as it is in + // the packet + uint16_t crc = 0xffff ^ (len & 0xff); + + for (int i = 0; i < len; i++) { + crc = (crc >> 8) | (crc << 8); + crc ^= buf[i]; + crc ^= (crc & 0xFF) >> 4; + crc ^= crc << 12; + crc ^= (crc & 0xFF) << 5; + } + + return crc; +} + +int main() { + pc.baud(38400); + uart.baud(38400); + + pc.printf("\n\r--------\n\rUART Test\n\r"); + + if (uart.readable()) { + pc.printf("Leftover characters: "); + while(uart.readable()) { + pc.printf("%c", uart.getc()); + } + pc.printf("\n\r"); + } + + nREQ.input(); + nREQ.mode(PullUp); + nRDY.input(); + nRDY.mode(PullUp); + + pc.printf("Waiting\n\r"); + + while(nREQ != 0) { + wait(0.1); + pc.printf("nREQ: %d\n\r", nREQ.read()); + } + + // pc.printf("nREQ has gone low\n\r"); + + nRDY = 0; + nRDY.output(); + + int len = uart.getc(); + pc.printf("len: %d\n\r", len); + std::vector<uint8_t> payload; + for (int i = 0; i < len; i++) { + payload.push_back(uart.getc()); + pc.printf("%d have recieved\n\r", payload.size()); + } + + uint8_t checksum = 0; + for (int i = 0; i < 2; i++) { + checksum |= ((uint16_t) (uart.getc())) << (i * 8); + } + + pc.printf("len: %d\n\r", len); + pc.printf("payload: "); + for (int i = 0; i < len; i++) { + pc.printf("%c", payload[i]); + } + pc.printf("\n\r"); + pc.printf("checksum: 0x%X\n\r", checksum); + + uint16_t crc = ccitt(len, &payload[0]); + pc.printf("ccitt: 0x%X\n\r", crc); + + nRDY.input(); + nRDY.mode(PullUp); + + pc.printf("Sending\n\r"); + + uint8_t* str = (uint8_t*) "HelloHelloHelloHelloHello"; + uint8_t str_len = 5; + // uint16_t str_checksum = ccitt(str_len, str); + + nREQ = 0; + nREQ.output(); + + while(nRDY != 0) { + wait(0.1); + } + + pc.printf("got nRDY\n\r"); + + uart.putc(str_len); + for (int i = 0; i < (str_len + 1); i++) { + uart.putc(str[i]); + } + uart.putc(0); + uart.putc(0); + + nREQ.input(); + nREQ.mode(PullUp); + + pc.printf("All done\n\r"); + + while (1) { + // if (uart.readable()) { + // pc.printf("%c", uart.getc()); + // } + } +} \ No newline at end of file