diff options
| -rw-r--r-- | arch/m68k/kernel/head.S | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/arch/m68k/kernel/head.S b/arch/m68k/kernel/head.S index b671f07..15c8f55 100644 --- a/arch/m68k/kernel/head.S +++ b/arch/m68k/kernel/head.S @@ -2722,6 +2722,7 @@ func_return get_new_page #define MAC_USE_SCC_B /* Printer port */ #if defined(MAC_USE_SCC_A) || defined(MAC_USE_SCC_B) +/* Initialisation table for SCC with 3.6864 MHz PCLK */ L(scc_initable_mac): .byte 4,0x44 /* x16, 1 stopbit, no parity */ .byte 3,0xc0 /* receiver: 8 bpc */ @@ -2744,14 +2745,12 @@ L(scc_initable_mac): #define USE_MFP #if defined(USE_SCC_A) || defined(USE_SCC_B) -#define USE_SCC -/* Initialisation table for SCC */ -L(scc_initable): - .byte 9,12 /* Reset */ +/* Initialisation table for SCC with 7.9872 MHz PCLK */ +/* PCLK == 8.0539 gives baud == 9680.1 */ +L(scc_initable_atari): .byte 4,0x44 /* x16, 1 stopbit, no parity */ .byte 3,0xc0 /* receiver: 8 bpc */ .byte 5,0xe2 /* transmitter: 8 bpc, assert dtr/rts */ - .byte 9,0 /* no interrupts */ .byte 10,0 /* NRZ */ .byte 11,0x50 /* use baud rate generator */ .byte 12,24,13,0 /* 9600 baud */ @@ -2800,7 +2799,7 @@ LMFP_UDR = 0xfffa2f */ /* - * Initialize serial port hardware for 9600/8/1 + * Initialize serial port hardware */ func_start serial_init,%d0/%d1/%a0/%a1 /* @@ -2810,7 +2809,7 @@ func_start serial_init,%d0/%d1/%a0/%a1 * d0 = boot info offset * CONFIG_ATARI * a0 = address of SCC - * a1 = Liobase address/address of scc_initable + * a1 = Liobase address/address of scc_initable_atari * d0 = init data for serial port * CONFIG_MAC * a0 = address of SCC @@ -2846,9 +2845,21 @@ func_start serial_init,%d0/%d1/%a0/%a1 moveb %a1@(LPSG_READ),%d0 bset #5,%d0 moveb %d0,%a1@(LPSG_WRITE) -#elif defined(USE_SCC) +#elif defined(USE_SCC_A) || defined(USE_SCC_B) lea %a1@(LSCC_CTRL),%a0 - lea %pc@(L(scc_initable)),%a1 + /* Reset SCC register pointer */ + moveb %a0@,%d0 + /* Reset SCC device: write register pointer then register value */ + moveb #9,%a0@ + moveb #0xc0,%a0@ + /* Wait for 5 PCLK cycles, which is about 63 CPU cycles */ + /* 5 / 7.9872 MHz = approx. 0.63 us = 63 / 100 MHz */ + movel #32,%d0 +2: + subq #1,%d0 + jne 2b + /* Initialize channel */ + lea %pc@(L(scc_initable_atari)),%a1 2: moveb %a1@+,%d0 jmi 3f moveb %d0,%a0@ @@ -3017,7 +3028,7 @@ func_start serial_putc,%d0/%d1/%a0/%a1 nop bset #5,%d0 moveb %d0,%a1@(LPSG_WRITE) -#elif defined(USE_SCC) +#elif defined(USE_SCC_A) || defined(USE_SCC_B) 3: btst #2,%a1@(LSCC_CTRL) jeq 3b moveb %d0,%a1@(LSCC_DATA) |
