static uint8_t dreamload_get_byte_old(void) {
unsigned int i;
iec_bus_t tmp;
uint8_t result = 0;
for (i=0; i<2; i++) {
/* shift bits to upper nibble */
result <<= 4;
/* wait until ATN is low */
while (IEC_ATN) ;
/* read two bits a moment later */
delay_us(3);
tmp = iec_bus_read();
result |= (!(tmp & IEC_BIT_CLOCK)) << 3;
result |= (!(tmp & IEC_BIT_DATA)) << 1;
/* wait until ATN is high */
while (!IEC_ATN) ;
/* read two bits a moment later */
delay_us(3);
tmp = iec_bus_read();
result |= (!(tmp & IEC_BIT_CLOCK)) << 2;
result |= (!(tmp & IEC_BIT_DATA)) << 0;
}
return result;
}
/**
* read_bus_at - reads the IEC bus at a certain time
* @time: read time in 100ns after reference_time
*
* This function returns the current IEC bus state at a certain time
* after the reference_time set by a previous wait_* function.
*/
static __attribute__((unused)) uint32_t read_bus_at(uint32_t time) {
/* check if requested time is possible */
// FIXME: Wrap in debugging macro?
if (IEC_TIMER_A->TC >= reference_time+time)
set_test_led(1);
// FIXME: This could be done in hardware using DMA
/* Wait until specified time */
while (IEC_TIMER_A->TC < reference_time+time) ;
return iec_bus_read();
}
/* DolphinDOS XQ command */
void load_dolphin(void) {
/* find the already open buffer */
buffer_t *buf = find_buffer(0);
if (!buf)
return;
buf->position = 2;
/* initial handshaking */
// note about the delays: 100us work, not optimized
// (doesn't matter much outside the loop)
delay_us(100); // experimental delay
parallel_set_dir(PARALLEL_DIR_OUT);
set_clock(0);
parallel_clear_rxflag();
delay_us(100); // experimental delay
parallel_send_handshake();
uart_flush();
delay_us(100); // experimental delay
/* every sector except the last */
uint8_t i;
while (!buf->sendeoi) {
iec_bus_t bus_state = iec_bus_read();
/* transmit first byte */
dolphin_write_hs(buf->data[2]);
/* check DATA state before transmission */
if (bus_state & IEC_BIT_DATA) {
cleanup_and_free_buffer(buf);
return;
}
/* transmit the rest of the sector */
for (i = 3; i != 0; i++)
dolphin_write_hs(buf->data[i]);
/* read next sector */
if (buf->refill(buf)) {
cleanup_and_free_buffer(buf);
return;
}
}
/* last sector */
i = 2;
do {
dolphin_write_hs(buf->data[i]);
} while (i++ < buf->lastused);
/* final handshake */
set_clock(1);
while (!IEC_DATA) ;
parallel_send_handshake();
parallel_set_dir(PARALLEL_DIR_IN);
cleanup_and_free_buffer(buf);
}
