1 /*-------------------------------------------------------------------------
2 tinibios.c - startup and serial routines for the DS80C400 (tested on TINIM400)
4 Written By - Johan Knol, johan.knol@iduna.nl
6 Further hacked by Kevin Vigor with invaluable assistance from Bob Heise.
8 This program is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by the
10 Free Software Foundation; either version 2, or (at your option) any
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22 In other words, you are welcome to use, share and improve this program.
23 You are forbidden to forbid anyone else to use, share and improve
24 what you give them. Help stamp out software-hoarding!
25 -------------------------------------------------------------------------*/
32 #define TIMED_ACCESS(sfr,value) { TA=0xaa; TA=0x55; sfr=value; }
35 #define OSCILLATOR 14745600
37 unsigned char _sdcc_external_startup(void)
39 IE = 0; // Disable all interrupts.
44 ; save the 24-bit return address
50 mov _ESP,#0x00; reinitialize the stack
53 ; restore the 24-bit return address
59 // Stub: call rom_init here, then fixup IVT.
62 Serial0Init(1, 0); // baud argument ignored.
64 IE = 0x80; // Enable interrupts.
69 // now the serial0 stuff
71 // just to make the code more readable
72 #define S0RBS SERIAL_0_RECEIVE_BUFFER_SIZE
74 // this is a ring buffer and can overflow at anytime!
75 static volatile unsigned char receive0Buffer[S0RBS];
76 static volatile int receive0BufferHead=0;
77 static volatile int receive0BufferTail=0;
78 // no buffering for transmit
79 static volatile char transmit0IsBusy=0;
81 static data unsigned char serial0Buffered;
83 /* Initialize serial0.
85 Available baudrates are from 110 upto 115200 (using 16-bit timer 2)
86 If baud==0, the port is disabled.
88 If buffered!=0, characters received are buffered using an interrupt
92 #define SERIAL0_BAUDRATE 115200
93 #define TIMER_RELOAD (65536 - ((OSCILLATOR) / (32 * SERIAL0_BAUDRATE)))
95 void Serial0Init (unsigned long baud, unsigned char buffered) {
97 ES0 = 0; // disable serial channel 0 interrupt
100 // Need no port setup, done by boot rom.
103 SCON0 = 0x5A; // 10 bit serial 0, use timer baud rate, enable recieving
104 RCAP2H = (TIMER_RELOAD >> 8) & 0xff;
105 RCAP2L = TIMER_RELOAD & 0xff;
106 T2CON = 0x30; // Enable timer 2 for serial port
107 TR2 = 1; // Set timer 2 to run
112 serial0Buffered=buffered;
115 installInterrupt(Serial0IrqHandler, 0x23);
116 RI_0=TI_0=0; // clear "pending" interrupts
117 ES0 = 1; // enable serial channel 0 interrupt
119 RI_0=0; // receive buffer empty
120 TI_0=1; // transmit buffer empty
124 void Serial0SwitchToBuffered(void)
129 installInterrupt(Serial0IrqHandler, 0x23);
130 RI_0=TI_0=0; // clear "pending" interrupts
131 ES0 = 1; // enable serial channel 0 interrupt
136 void Serial0IrqHandler (void) interrupt 4 {
138 receive0Buffer[receive0BufferHead]=SBUF0;
139 receive0BufferHead=(receive0BufferHead+1)&(S0RBS-1);
140 if (receive0BufferHead==receive0BufferTail) {
141 /* buffer overrun, sorry :) */
142 receive0BufferTail=(receive0BufferTail+1)&(S0RBS-1);
152 char Serial0CharArrived(void) {
153 if (serial0Buffered) {
154 if (receive0BufferHead!=receive0BufferTail)
155 return receive0Buffer[receive0BufferTail];
163 void Serial0PutChar (char c)
165 if (serial0Buffered) {
166 while (transmit0IsBusy)
178 char Serial0GetChar (void)
181 if (serial0Buffered) {
182 while (receive0BufferHead==receive0BufferTail)
184 c=receive0Buffer[receive0BufferTail];
185 ES0=0; // disable serial interrupts
186 receive0BufferTail=(receive0BufferTail+1)&(S0RBS-1);
187 ES0=1; // enable serial interrupts
197 void Serial0SendBreak() {
199 ClockMilliSecondsDelay(2);
203 void Serial0Flush() {
204 ES0=0; // disable interrupts
205 receive0BufferHead=receive0BufferTail=0;
207 if (serial0Buffered) {
209 ES0=1; // enable interrupts
215 // now let's go for the clock stuff - on the DS400, we can just
216 // use the ROM's millisecond timer, running off timer 0.
218 // for now, this timer runs too fast by about 20%. We need an implementation of
219 // task_settickreload to fix this.
222 // nada, all done by DSS_rom_init
225 // we can't just use milliSeconds
226 unsigned long ClockTicks(void) {
227 return DSS_gettimemillis();
230 void ClockMilliSecondsDelay(unsigned long delay) {
231 unsigned long ms = DSS_gettimemillis() + delay;
233 while (ms > DSS_gettimemillis())