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mcd, some improvements (dma timing, interrupt handling)

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kub 2024-04-19 21:08:09 +02:00
parent 4447902711
commit 691abdfa0f
3 changed files with 22 additions and 19 deletions
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15
pico/cd/cdc.c
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@ -66,6 +66,7 @@
/* PicoDrive: doing DMA at once, not using callbacks */
//#define DMA_BYTES_PER_LINE 512
#define DMA_CYCLES_PER_BYTE 4 // or 6?
enum dma_type {
word_ram_0_dma_w = 1,
@ -354,7 +355,7 @@ void cdc_dma_update(void)
do_dma(cdc.dma_w, cdc.dbc + 1);
/* reset data byte counter (DBCH bits 4-7 should be set to 1) */
cdc.dbc = 0xf000;
cdc.dbc = 0xffff;
/* clear !DTEN and !DTBSY */
cdc.ifstat |= (BIT_DTBSY | BIT_DTEN);
@ -405,6 +406,9 @@ int cdc_decoder_update(uint8 header[4])
/* set !VALST */
cdc.stat[3] = 0x00;
/* set CRCOK bit */
cdc.stat[0] = BIT_DECEN;
/* pending decoder interrupt */
cdc.ifstat &= ~BIT_DECI;
@ -602,7 +606,7 @@ void cdc_reg_w(unsigned char data)
}
if (cdc.dma_w)
pcd_event_schedule_s68k(PCD_EVENT_DMA, cdc.dbc / 2);
pcd_event_schedule_s68k(PCD_EVENT_DMA, cdc.dbc * DMA_CYCLES_PER_BYTE);
}
Pico_mcd->s68k_regs[0x04+1] = 0x07;
@ -643,11 +647,8 @@ void cdc_reg_w(unsigned char data)
case 0x0a: /* CTRL0 */
{
/* set CRCOK bit only if decoding is enabled */
cdc.stat[0] = data & BIT_DECEN;
/* reset DECI if decoder turned off */
if (!cdc.stat[0])
if (!(data & BIT_DECEN))
cdc.ifstat |= BIT_DECI;
/* update decoding mode */
@ -827,7 +828,7 @@ unsigned short cdc_host_r(void)
if ((int16)cdc.dbc <= 0)
{
/* reset data byte counter (DBCH bits 4-7 should be set to 1) */
cdc.dbc = 0xf000;
cdc.dbc = 0xffff;
/* clear !DTEN and !DTBSY */
cdc.ifstat |= (BIT_DTBSY | BIT_DTEN);