Tianji Wu
HW2 implemented using busy loop
main.cpp@0:9db2667ac0d3, 2010-12-01 (annotated)
- Committer:
- the729
- Date:
- Wed Dec 01 02:53:33 2010 +0000
- Revision:
- 0:9db2667ac0d3
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| the729 | 0:9db2667ac0d3 | 1 | #include "mbed.h" |
| the729 | 0:9db2667ac0d3 | 2 | |
| the729 | 0:9db2667ac0d3 | 3 | //DigitalOut led1(LED1); |
| the729 | 0:9db2667ac0d3 | 4 | //DigitalOut led2(LED2); |
| the729 | 0:9db2667ac0d3 | 5 | |
| the729 | 0:9db2667ac0d3 | 6 | Serial pc(USBTX, USBRX); |
| the729 | 0:9db2667ac0d3 | 7 | |
| the729 | 0:9db2667ac0d3 | 8 | #define BTN0 p15 |
| the729 | 0:9db2667ac0d3 | 9 | #define BTN1 p20 |
| the729 | 0:9db2667ac0d3 | 10 | #define MAX_LENGTH 32 |
| the729 | 0:9db2667ac0d3 | 11 | |
| the729 | 0:9db2667ac0d3 | 12 | typedef unsigned int uint32_t; |
| the729 | 0:9db2667ac0d3 | 13 | typedef unsigned char uint8_t; |
| the729 | 0:9db2667ac0d3 | 14 | |
| the729 | 0:9db2667ac0d3 | 15 | void precharge(PinName p) |
| the729 | 0:9db2667ac0d3 | 16 | { |
| the729 | 0:9db2667ac0d3 | 17 | DigitalIn prec(p); |
| the729 | 0:9db2667ac0d3 | 18 | prec.mode(PullUp); |
| the729 | 0:9db2667ac0d3 | 19 | prec.mode(PullNone); |
| the729 | 0:9db2667ac0d3 | 20 | } |
| the729 | 0:9db2667ac0d3 | 21 | |
| the729 | 0:9db2667ac0d3 | 22 | uint8_t read_cap() |
| the729 | 0:9db2667ac0d3 | 23 | { |
| the729 | 0:9db2667ac0d3 | 24 | precharge(BTN0); |
| the729 | 0:9db2667ac0d3 | 25 | precharge(BTN1); |
| the729 | 0:9db2667ac0d3 | 26 | wait_ms(5); |
| the729 | 0:9db2667ac0d3 | 27 | float s0 = AnalogIn(BTN0); |
| the729 | 0:9db2667ac0d3 | 28 | float s1 = AnalogIn(BTN1); |
| the729 | 0:9db2667ac0d3 | 29 | //pc.printf("%f \r", s0); |
| the729 | 0:9db2667ac0d3 | 30 | return ((s0>0.5)?0:1) + ((s1>0.5)?0:2); |
| the729 | 0:9db2667ac0d3 | 31 | } |
| the729 | 0:9db2667ac0d3 | 32 | |
| the729 | 0:9db2667ac0d3 | 33 | int main() |
| the729 | 0:9db2667ac0d3 | 34 | { |
| the729 | 0:9db2667ac0d3 | 35 | enum { |
| the729 | 0:9db2667ac0d3 | 36 | IDLE=0, |
| the729 | 0:9db2667ac0d3 | 37 | HOST_INPUT, |
| the729 | 0:9db2667ac0d3 | 38 | USER_INPUT |
| the729 | 0:9db2667ac0d3 | 39 | } state; |
| the729 | 0:9db2667ac0d3 | 40 | uint8_t c = 0; |
| the729 | 0:9db2667ac0d3 | 41 | uint32_t data = 0; |
| the729 | 0:9db2667ac0d3 | 42 | uint8_t datalength = 0; |
| the729 | 0:9db2667ac0d3 | 43 | |
| the729 | 0:9db2667ac0d3 | 44 | state = IDLE; |
| the729 | 0:9db2667ac0d3 | 45 | while (1) { |
| the729 | 0:9db2667ac0d3 | 46 | switch(state) { |
| the729 | 0:9db2667ac0d3 | 47 | case IDLE: |
| the729 | 0:9db2667ac0d3 | 48 | pc.putc(c = pc.getc()); |
| the729 | 0:9db2667ac0d3 | 49 | if (c == 'S') { |
| the729 | 0:9db2667ac0d3 | 50 | datalength = 0; |
| the729 | 0:9db2667ac0d3 | 51 | state = HOST_INPUT; |
| the729 | 0:9db2667ac0d3 | 52 | } else { |
| the729 | 0:9db2667ac0d3 | 53 | pc.printf("HOST ERROR. You are supposed to input S. Try again. \r\n"); |
| the729 | 0:9db2667ac0d3 | 54 | } |
| the729 | 0:9db2667ac0d3 | 55 | break; |
| the729 | 0:9db2667ac0d3 | 56 | case HOST_INPUT: |
| the729 | 0:9db2667ac0d3 | 57 | pc.putc(c = pc.getc()); |
| the729 | 0:9db2667ac0d3 | 58 | if (c == '0' || c == '1') { |
| the729 | 0:9db2667ac0d3 | 59 | datalength ++; |
| the729 | 0:9db2667ac0d3 | 60 | if (datalength > MAX_LENGTH) { |
| the729 | 0:9db2667ac0d3 | 61 | pc.printf("\r\nLength execeeds maximum. \r\n"); |
| the729 | 0:9db2667ac0d3 | 62 | } else { |
| the729 | 0:9db2667ac0d3 | 63 | data = (data << 1) | (c-'0'); |
| the729 | 0:9db2667ac0d3 | 64 | } |
| the729 | 0:9db2667ac0d3 | 65 | } else if (c == 'E') { |
| the729 | 0:9db2667ac0d3 | 66 | pc.printf("\r\nInput End. Tap the caps now. \r\n"); |
| the729 | 0:9db2667ac0d3 | 67 | if (!datalength) { |
| the729 | 0:9db2667ac0d3 | 68 | pc.printf("Zero length. Try again. \r\n"); |
| the729 | 0:9db2667ac0d3 | 69 | state = IDLE; |
| the729 | 0:9db2667ac0d3 | 70 | break; |
| the729 | 0:9db2667ac0d3 | 71 | } |
| the729 | 0:9db2667ac0d3 | 72 | data <<= (32-datalength); |
| the729 | 0:9db2667ac0d3 | 73 | state = USER_INPUT; |
| the729 | 0:9db2667ac0d3 | 74 | } else { |
| the729 | 0:9db2667ac0d3 | 75 | pc.printf("\r\nHOST ERROR. \r\n"); |
| the729 | 0:9db2667ac0d3 | 76 | } |
| the729 | 0:9db2667ac0d3 | 77 | break; |
| the729 | 0:9db2667ac0d3 | 78 | case USER_INPUT: |
| the729 | 0:9db2667ac0d3 | 79 | c = read_cap(); |
| the729 | 0:9db2667ac0d3 | 80 | if (!c) break; |
| the729 | 0:9db2667ac0d3 | 81 | wait_ms(10); |
| the729 | 0:9db2667ac0d3 | 82 | if (c != read_cap()) break; |
| the729 | 0:9db2667ac0d3 | 83 | while(read_cap()); |
| the729 | 0:9db2667ac0d3 | 84 | if (c == 3) { |
| the729 | 0:9db2667ac0d3 | 85 | pc.printf("\r\nTOUCH ERROR. Touch only one. \r\n"); |
| the729 | 0:9db2667ac0d3 | 86 | break; |
| the729 | 0:9db2667ac0d3 | 87 | } |
| the729 | 0:9db2667ac0d3 | 88 | c -= 1; |
| the729 | 0:9db2667ac0d3 | 89 | pc.putc(c + '0'); |
| the729 | 0:9db2667ac0d3 | 90 | if (c == (data >> 31)) { |
| the729 | 0:9db2667ac0d3 | 91 | datalength--; |
| the729 | 0:9db2667ac0d3 | 92 | if (!datalength) { |
| the729 | 0:9db2667ac0d3 | 93 | pc.printf("\r\nMATCH! \r\n"); |
| the729 | 0:9db2667ac0d3 | 94 | state = IDLE; |
| the729 | 0:9db2667ac0d3 | 95 | } |
| the729 | 0:9db2667ac0d3 | 96 | data <<= 1; |
| the729 | 0:9db2667ac0d3 | 97 | } else { |
| the729 | 0:9db2667ac0d3 | 98 | pc.printf("\r\nTOUCH ERROR. \r\n"); |
| the729 | 0:9db2667ac0d3 | 99 | } |
| the729 | 0:9db2667ac0d3 | 100 | break; |
| the729 | 0:9db2667ac0d3 | 101 | } |
| the729 | 0:9db2667ac0d3 | 102 | } |
| the729 | 0:9db2667ac0d3 | 103 | } |