IEEE 802.15.4 subsystem
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| 1 | /* |
| 2 | * fw/spi.c - ATmega8 family SPI I/O |
| 3 | * |
| 4 | * Written 2011, 2013 by Werner Almesberger |
| 5 | * Copyright 2011, 2013 Werner Almesberger |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | */ |
| 12 | |
| 13 | |
| 14 | #include <stdbool.h> |
| 15 | #include <stdint.h> |
| 16 | |
| 17 | #include <avr/io.h> |
| 18 | |
| 19 | #include "board.h" |
| 20 | #include "spi.h" |
| 21 | |
| 22 | |
| 23 | static bool spi_initialized = 0; |
| 24 | |
| 25 | |
| 26 | void spi_begin(void) |
| 27 | { |
| 28 | if (!spi_initialized) |
| 29 | spi_init(); |
| 30 | CLR(nSS); |
| 31 | } |
| 32 | |
| 33 | |
| 34 | uint8_t spi_io(uint8_t v) |
| 35 | { |
| 36 | // while (!(UCSR1A & 1 << UDRE1)); |
| 37 | UDR1 = v; |
| 38 | while (!(UCSR1A & 1 << RXC1)); |
| 39 | return UDR1; |
| 40 | } |
| 41 | |
| 42 | |
| 43 | void spi_end(void) |
| 44 | { |
| 45 | // while (!(UCSR1A & 1 << TXC1)); |
| 46 | SET(nSS); |
| 47 | } |
| 48 | |
| 49 | |
| 50 | void spi_recv_block(uint8_t *buf, uint8_t n) |
| 51 | { |
| 52 | if (!n) |
| 53 | return; |
| 54 | UDR1 = 0; |
| 55 | while (--n) { |
| 56 | while (!(UCSR1A & 1 << RXC1)); |
| 57 | *buf++ = UDR1; |
| 58 | UDR1 = 0; |
| 59 | } |
| 60 | while (!(UCSR1A & 1 << RXC1)); |
| 61 | *buf++ = UDR1; |
| 62 | } |
| 63 | |
| 64 | |
| 65 | void spi_off(void) |
| 66 | { |
| 67 | spi_initialized = 0; |
| 68 | UCSR1B = 0; |
| 69 | } |
| 70 | |
| 71 | |
| 72 | void spi_init(void) |
| 73 | { |
| 74 | SET(nSS); |
| 75 | OUT(SCLK); |
| 76 | OUT(MOSI); |
| 77 | OUT(nSS); |
| 78 | IN(MISO); |
| 79 | |
| 80 | UBRR1 = 0; /* set bit rate to zero to begin */ |
| 81 | UCSR1C = 1 << UMSEL11 | 1 << UMSEL10; |
| 82 | /* set MSPI, MSB first, SPI data mode 0 */ |
| 83 | UCSR1B = 1 << RXEN1 | 1 << TXEN1; |
| 84 | /* enable receiver and transmitter */ |
| 85 | UBRR1 = 0; /* reconfirm the bit rate */ |
| 86 | |
| 87 | spi_initialized = 1; |
| 88 | } |
| 89 |
