C8051F32x firmware infrastructure
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| 1 | /* |
| 2 | * common/uart.c - UART initialization and debug output |
| 3 | * |
| 4 | * Written 2008, 2009 by Werner Almesberger |
| 5 | * Copyright 2008, 2009 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 <stdarg.h> |
| 15 | #include <stdio.h> |
| 16 | |
| 17 | #include "regs.h" |
| 18 | #include "uart.h" |
| 19 | |
| 20 | |
| 21 | /* gpio j4=0 */ |
| 22 | |
| 23 | |
| 24 | #ifndef CONFIG_USB_PUTCHAR |
| 25 | |
| 26 | void putchar(char c) |
| 27 | { |
| 28 | if (c == '\n') |
| 29 | putchar('\r'); |
| 30 | SBUF0 = c; |
| 31 | while (!TI0); |
| 32 | TI0 = 0; |
| 33 | } |
| 34 | |
| 35 | #endif /* !CONFIG_USB_PUTCHAR */ |
| 36 | |
| 37 | |
| 38 | /* for now, we always use printf_tiny, which doesn't have a vprintf* version */ |
| 39 | #ifdef noCONFIG_PRINTK |
| 40 | |
| 41 | void printk(const char *fmt, ...) |
| 42 | { |
| 43 | va_list ap; |
| 44 | __bit saved; |
| 45 | |
| 46 | va_start(ap, fmt); |
| 47 | saved = EA; |
| 48 | EA = 0; |
| 49 | vprintf(fmt, ap); |
| 50 | EA = saved; |
| 51 | va_end(ap); |
| 52 | } |
| 53 | |
| 54 | #endif /* CONFIG_PRINTK */ |
| 55 | |
| 56 | |
| 57 | void uart_init(uint8_t brg_mhz) |
| 58 | { |
| 59 | /* |
| 60 | * UART: Enable only transmitter, no interrupts. |
| 61 | */ |
| 62 | SCON0 = 0; /* also clears TI0 */ |
| 63 | SMOD0 = S0DL1 | S0DL0; |
| 64 | |
| 65 | /* |
| 66 | * Configure the UART to 115200bps, see table 13.1 |
| 67 | * |
| 68 | * We can's support 1.5MHz (that is, without using the USB clock, but |
| 69 | * why would one want to run the core at 1.5MHz when USB is around ?) |
| 70 | * |
| 71 | * The closes settings would be: |
| 72 | * |
| 73 | * SBRL0 = 0xfff9; -- 107142.9 bps, error = -7% |
| 74 | * SBRL0 = 0xfffa; -- 125000 bps, error = +8.5% |
| 75 | * |
| 76 | * Depending on signal quality, we would need something like +/-5%. |
| 77 | */ |
| 78 | |
| 79 | #if defined(UART_115200_BPS) |
| 80 | switch (brg_mhz) { |
| 81 | case 3: |
| 82 | SBRL0 = 0xfff3; |
| 83 | break; |
| 84 | case 6: |
| 85 | SBRL0 = 0xffe6; |
| 86 | break; |
| 87 | case 12: |
| 88 | SBRL0 = 0xffcc; |
| 89 | break; |
| 90 | case 24: |
| 91 | SBRL0 = 0xff98; |
| 92 | break; |
| 93 | case 48: |
| 94 | SBRL0 = 0xff30; |
| 95 | break; |
| 96 | } |
| 97 | #elif defined(UART_57600_BPS) |
| 98 | switch (brg_mhz) { |
| 99 | case 3: |
| 100 | SBRL0 = 0xffe6; |
| 101 | break; |
| 102 | case 6: |
| 103 | SBRL0 = 0xffcc; |
| 104 | break; |
| 105 | case 12: |
| 106 | SBRL0 = 0xff98; |
| 107 | break; |
| 108 | case 24: |
| 109 | SBRL0 = 0xff30; |
| 110 | break; |
| 111 | case 48: |
| 112 | SBRL0 = 0xfe5f; |
| 113 | break; |
| 114 | } |
| 115 | #else |
| 116 | #error "must set either UART_115200_BPS or UART_57600_BPS" |
| 117 | #endif |
| 118 | |
| 119 | SBCON0 = SB0RUN | SB0PS0 | SB0PS1; |
| 120 | |
| 121 | /* |
| 122 | * Make TX a push-pull output |
| 123 | */ |
| 124 | P0MDOUT |= 1 << 4; |
| 125 | } |
| 126 |
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