From e1c7a3b69be7d6fbf6c5b1c649af841179e9076c Mon Sep 17 00:00:00 2001 From: Joakim Larsson Edstrom Date: Wed, 18 Dec 2019 12:39:41 +0100 Subject: [PATCH] mc6854: WIP added support for external clocks and DMA --- src/devices/machine/mc6854.cpp | 198 ++++++++++++++++++++------------- src/devices/machine/mc6854.h | 17 ++- 2 files changed, 132 insertions(+), 83 deletions(-) diff --git a/src/devices/machine/mc6854.cpp b/src/devices/machine/mc6854.cpp index 488d3872745..f4a39617b02 100644 --- a/src/devices/machine/mc6854.cpp +++ b/src/devices/machine/mc6854.cpp @@ -22,7 +22,6 @@ TODO: - CRC - - DMA mode - loop mode - status prioritization - NRZI vs. NRZ coding @@ -34,9 +33,20 @@ #include "emu.h" #include "mc6854.h" -//#define VERBOSE 1 +#define LOG_SETUP (1U << 1) +#define LOG_BITS (1U << 2) + +//#define VERBOSE (LOG_BITS|LOG_GENERAL | LOG_SETUP) +//#define LOG_OUTPUT_STREAM std::cout + #include "logmacro.h" +#define LOGSETUP(...) LOGMASKED(LOG_SETUP, __VA_ARGS__) +#define LOGBITS(...) LOGMASKED(LOG_BITS, __VA_ARGS__) + +//#define VERBOSE 1 +//#include "logmacro.h" + /******************* parameters ******************/ @@ -66,6 +76,9 @@ constexpr unsigned mc6854_device::MAX_FRAME_LENGTH; #define RIE ( m_cr1 & 2 ) /* interrupt enable */ #define TIE ( m_cr1 & 4 ) +#define RDSR ( m_cr1 & 8 ) /* DMA mode */ +#define TDSR ( m_cr1 & 0x10 ) + #define DISCONTINUE ( m_cr1 & 0x20 ) /* discontinue received frame */ @@ -131,6 +144,8 @@ DEFINE_DEVICE_TYPE(MC6854, mc6854_device, "mc6854", "Motorola MC6854 ADLC") mc6854_device::mc6854_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) : device_t(mconfig, MC6854, tag, owner, clock), m_out_irq_cb(*this), + m_out_rdsr_cb(*this), + m_out_tdsr_cb(*this), m_out_txd_cb(*this), m_out_frame_cb(*this), m_out_rts_cb(*this), @@ -150,6 +165,8 @@ mc6854_device::mc6854_device(const machine_config &mconfig, const char *tag, dev m_rreg(0), m_rones(0), m_rsize(0), + m_rxd(0), + m_rxc(0), m_flen(0), m_fpos(0) { @@ -172,6 +189,8 @@ mc6854_device::mc6854_device(const machine_config &mconfig, const char *tag, dev void mc6854_device::device_start() { m_out_irq_cb.resolve_safe(); + m_out_rdsr_cb.resolve_safe(); + m_out_tdsr_cb.resolve_safe(); m_out_txd_cb.resolve(); m_out_frame_cb.resolve(); m_out_rts_cb.resolve_safe(); @@ -391,6 +410,7 @@ TIMER_CALLBACK_MEMBER(mc6854_device::tfifo_cb) /* data underrun => abort */ logerror( "%f mc6854_tfifo_cb: FIFO underrun\n", machine().time().as_double() ); m_sr1 |= TU; + update_sr1(); m_tstate = 0; send_bits( 0xffff, ABTEX ? 16 : 8, 0 ); m_flen = 0; @@ -514,10 +534,10 @@ void mc6854_device::rfifo_push( uint8_t d ) } m_rsize -= blen; + update_sr1( ); } - void mc6854_device::rfifo_terminate( ) { /* mark most recently pushed byte as the last one of the frame */ @@ -537,7 +557,6 @@ void mc6854_device::rfifo_terminate( ) } - /* CPU pops the FIFO */ uint8_t mc6854_device::rfifo_pop( ) { @@ -566,70 +585,9 @@ uint8_t mc6854_device::rfifo_pop( ) } -/* MC6854 makes fields from bits */ WRITE_LINE_MEMBER( mc6854_device::set_rx ) { - int fieldlen = ( m_rstate < 6 ) ? 8 : RWL; - - if ( RRESET || (m_sr2 & DCD) ) - return; - - if ( state ) - { - m_rones++; - m_rreg = (m_rreg >> 1) | 0x80000000; - if ( m_rones >= 8 ) - { - /* abort */ - m_rstate = 0; - m_rsize = 0; - if ( m_rstate > 1 ) - { - /* only in-frame abort */ - m_sr2 |= RABT; - LOG( "%f mc6854_receive_bit: abort\n", machine().time().as_double() ); - } - } - else - { - m_rsize++; - if ( m_rstate && m_rsize >= fieldlen + 24 ) - rfifo_push( m_rreg ); - } - } - else if ( m_rones == 5 ) - { - /* discards '0' inserted after 5 '1' */ - m_rones = 0; - return; - } - else if ( m_rones == 6 ) - { - /* flag */ - if ( FDSE ) - m_sr1 |= FD; - - if ( m_rstate > 1 ) - { - /* end of frame */ - m_rreg >>= 1; - m_rsize++; - if ( m_rsize >= fieldlen + 24 ) /* last field */ - rfifo_push( m_rreg ); - rfifo_terminate( ); - LOG( "%f mc6854_receive_bit: end of frame\n", machine().time().as_double() ); - } - m_rones = 0; - m_rstate = 1; - m_rsize = 0; - } else - { - m_rones = 0; - m_rreg >>= 1; - m_rsize++; - if ( m_rstate && m_rsize >= fieldlen + 24 ) - rfifo_push( m_rreg ); - } + m_rxd = state; } @@ -663,7 +621,10 @@ int mc6854_device::send_frame( uint8_t* data, int len ) } memcpy( m_frame, data, len ); if ( FDSE ) + { m_sr1 |= FD; + update_sr1(); + } m_flen = len; m_fpos = 0; rfifo_push( m_frame[ m_fpos++ ] ); @@ -689,6 +650,7 @@ WRITE_LINE_MEMBER( mc6854_device::set_cts ) m_sr1 |= CTS; else m_sr1 &= ~CTS; + update_sr1(); } @@ -737,7 +699,7 @@ void mc6854_device::update_sr1( ) else m_sr1 &= ~S2RQ; - /* update TRDA (always prioritized by CTS) */ + /* update TDRA (always prioritized by CTS) */ if ( TRESET || ( m_sr1 & CTS ) ) m_sr1 &= ~TDRA; else @@ -757,9 +719,9 @@ void mc6854_device::update_sr1( ) /* update IRQ */ m_sr1 &= ~IRQ; - if ( RIE && (m_sr1 & (TU | TDRA) ) ) + if ( TIE && (m_sr1 & (TU | TDRA)) && !TDSR ) m_sr1 |= IRQ; - if ( TIE ) + if ( RIE && !RDSR ) { if ( m_sr1 & (S2RQ | RDA | CTS) ) m_sr1 |= IRQ; @@ -768,6 +730,8 @@ void mc6854_device::update_sr1( ) } m_out_irq_cb((m_sr1 & IRQ) ? ASSERT_LINE : CLEAR_LINE); + m_out_rdsr_cb((m_sr1 & RDA) ? ASSERT_LINE : CLEAR_LINE); + m_out_tdsr_cb((m_sr1 & TDRA) ? ASSERT_LINE : CLEAR_LINE); } @@ -802,6 +766,7 @@ uint8_t mc6854_device::read(offs_t offset) uint8_t data = rfifo_pop( ); LOG( "%f %s mc6854_r: get data $%02X\n", machine().time().as_double(), machine().describe_context(), data ); + m_out_rdsr_cb(CLEAR_LINE); // Deactive DMA request line regardless of mode return data; } @@ -819,15 +784,13 @@ void mc6854_device::write(offs_t offset, uint8_t data) { case 0: /* control register 1 */ m_cr1 = data; - LOG( "%f %s mc6854_w: set CR1=$%02X (ac=%i,irq=%c%c,%sreset=%c%c)\n", + LOGSETUP( "%f %s mc6854_w: set CR1=$%02X (ac=%i,irq=%c%c,%sreset=%c%c)\n", machine().time().as_double(), machine().describe_context(), m_cr1, AC ? 1 : 0, RIE ? 'r' : '-', TIE ? 't' : '-', DISCONTINUE ? "discontinue," : "", RRESET ? 'r' : '-', TRESET ? 't' : '-' ); - if ( m_cr1 & 0xc ) - logerror( "%s mc6854 DMA not handled (CR1=$%02X)\n", - machine().describe_context(), m_cr1 ); + if ( DISCONTINUE ) { /* abort receive FIFO but keeps shift register & synchro */ @@ -841,12 +804,14 @@ void mc6854_device::write(offs_t offset, uint8_t data) m_sr1 &= ~FD; m_sr2 &= ~(AP | FV | RIDLE | RABT | ERR | OVRN | DCD); if ( m_dcd ) m_sr2 |= DCD; + update_sr1( ); } if ( TRESET ) { tfifo_clear( ); m_sr1 &= ~(TU | TDRA | CTS); if ( m_cts ) m_sr1 |= CTS; + update_sr1( ); } break; @@ -855,7 +820,7 @@ void mc6854_device::write(offs_t offset, uint8_t data) { /* control register 3 */ m_cr3 = data; - LOG( "%f %s mc6854_w: set CR3=$%02X (lcf=%i,aex=%i,idl=%i,fdse=%i,loop=%i,tst=%i,dtr=%i)\n", + LOGSETUP( "%f %s mc6854_w: set CR3=$%02X (lcf=%i,aex=%i,idl=%i,fdse=%i,loop=%i,tst=%i,dtr=%i)\n", machine().time().as_double(), machine().describe_context(), m_cr3, LCF ? (CEX ? 16 : 8) : 0, AEX ? 1 : 0, IDL0 ? 0 : 1, FDSE ? 1 : 0, LOOP ? 1 : 0, @@ -872,7 +837,7 @@ void mc6854_device::write(offs_t offset, uint8_t data) { /* control register 2 */ m_cr2 = data; - LOG( "%f %s mc6854_w: set CR2=$%02X (pse=%i,bytes=%i,fmidle=%i,%s,tlast=%i,clr=%c%c,rts=%i)\n", + LOGSETUP( "%f %s mc6854_w: set CR2=$%02X (pse=%i,bytes=%i,fmidle=%i,%s,tlast=%i,clr=%c%c,rts=%i)\n", machine().time().as_double(), machine().describe_context(), m_cr2, PSE ? 1 : 0, TWOBYTES ? 2 : 1, FMIDLE ? 1 : 0, FCTDRA ? "fc" : "tdra", TLAST ? 1 : 0, @@ -889,6 +854,7 @@ void mc6854_device::write(offs_t offset, uint8_t data) m_sr2 &= ~(AP | FV | RIDLE | RABT | ERR | OVRN | DCD); if ( m_dcd ) m_sr2 |= DCD; + update_sr1( ); } if ( data & 0x40 ) { @@ -896,6 +862,7 @@ void mc6854_device::write(offs_t offset, uint8_t data) m_sr1 &= ~(TU | TDRA | CTS); if ( m_cts ) m_sr1 |= CTS; + update_sr1( ); } m_out_rts_cb( RTS ? 1 : 0 ); @@ -903,7 +870,7 @@ void mc6854_device::write(offs_t offset, uint8_t data) break; case 2: /* transmitter data: continue data */ - LOG( "%f %smc6854_w: push data=$%02X\n", machine().time().as_double(), machine().describe_context(), data ); + LOGSETUP( "%f %smc6854_w: push data=$%02X\n", machine().time().as_double(), machine().describe_context(), data ); tfifo_push( data ); break; @@ -912,7 +879,7 @@ void mc6854_device::write(offs_t offset, uint8_t data) { /* control register 4 */ m_cr4 = data; - LOG( "%f %s mc6854_w: set CR4=$%02X (interframe=%i,tlen=%i,rlen=%i,%s%s)\n", machine().time().as_double(), machine().describe_context(), m_cr4, + LOGSETUP( "%f %s mc6854_w: set CR4=$%02X (interframe=%i,tlen=%i,rlen=%i,%s%s)\n", machine().time().as_double(), machine().describe_context(), m_cr4, TWOINTER ? 2 : 1, TWL, RWL, ABT ? ( ABTEX ? "abort-ext," : "abort,") : "", @@ -927,7 +894,7 @@ void mc6854_device::write(offs_t offset, uint8_t data) else { /* transmitter data: last data */ - LOG( "%f %s mc6854_w: push last-data=$%02X\n", machine().time().as_double(), machine().describe_context(), data ); + LOGSETUP( "%f %s mc6854_w: push last-data=$%02X\n", machine().time().as_double(), machine().describe_context(), data ); tfifo_push( data ); tfifo_terminate( ); } @@ -938,9 +905,82 @@ void mc6854_device::write(offs_t offset, uint8_t data) } } +inline bool mc6854_device::receive_allowed() const +{ + return (!RRESET && !(m_sr2 & DCD)); +} + +/* MC6854 makes fields from bits */ WRITE_LINE_MEMBER( mc6854_device::rxc_w ) { - // TODO + if (receive_allowed() && state && !m_rxc) + { + int fieldlen = ( m_rstate < 6 ) ? 8 : RWL; + + if ( m_rxd ) + { + LOGBITS("I "); + m_rones++; + m_rreg = (m_rreg >> 1) | 0x80000000; + if ( m_rones >= 8 ) + { + /* abort */ + m_rstate = 0; + m_rsize = 0; + if ( m_rstate > 1 ) + { + /* only in-frame abort */ + m_sr2 |= RABT; + LOG( "%f mc6854_receive_bit: abort\n", machine().time().as_double() ); + } + } + else + { + m_rsize++; + if ( m_rstate && m_rsize >= fieldlen + 24 ) + rfifo_push( m_rreg ); + } + } + else if ( m_rones == 5 ) + { + /* discards '0' inserted after 5 '1' */ + LOGBITS("A zero is discarded\n"); + m_rones = 0; + return; + } + else if ( m_rones == 6 ) + { + /* flag */ + if ( FDSE ) + { + m_sr1 |= FD; + update_sr1( ); + } + + if ( m_rstate > 1 ) + { + /* end of frame */ + m_rreg >>= 1; + m_rsize++; + if ( m_rsize >= fieldlen + 24 ) /* last field */ + rfifo_push( m_rreg ); + rfifo_terminate( ); + LOG( "%f mc6854_receive_bit: end of frame\n", machine().time().as_double() ); + } + m_rones = 0; + m_rstate = 1; + m_rsize = 0; + } else + { + LOGBITS("O "); + m_rones = 0; + m_rreg >>= 1; + m_rsize++; + if ( m_rstate && m_rsize >= fieldlen + 24 ) + rfifo_push( m_rreg ); + } + } + m_rxc = state; } WRITE_LINE_MEMBER( mc6854_device::txc_w ) diff --git a/src/devices/machine/mc6854.h b/src/devices/machine/mc6854.h index defd3aa76c1..2e2fe6fa663 100644 --- a/src/devices/machine/mc6854.h +++ b/src/devices/machine/mc6854.h @@ -23,16 +23,19 @@ public: mc6854_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock = 0); - auto out_irq_cb() { return m_out_irq_cb.bind(); } - auto out_txd_cb() { return m_out_txd_cb.bind(); } - auto out_rts_cb() { return m_out_rts_cb.bind(); } - auto out_dtr_cb() { return m_out_dtr_cb.bind(); } + auto out_irq_cb() { return m_out_irq_cb.bind(); } + auto out_rdsr_cb() { return m_out_rdsr_cb.bind(); } + auto out_tdsr_cb() { return m_out_tdsr_cb.bind(); } + auto out_txd_cb() { return m_out_txd_cb.bind(); } + auto out_rts_cb() { return m_out_rts_cb.bind(); } + auto out_dtr_cb() { return m_out_dtr_cb.bind(); } template void set_out_frame_callback(T &&... args) { m_out_frame_cb.set(std::forward(args)...); } /* interface to CPU via address/data bus*/ uint8_t read(offs_t offset); void write(offs_t offset, uint8_t data); + uint8_t dma_r(){ return read(2); } /* low-level, bit-based interface */ DECLARE_WRITE_LINE_MEMBER( set_rx ); @@ -52,12 +55,15 @@ protected: // device-level overrides virtual void device_start() override; virtual void device_reset() override; + bool receive_allowed() const; private: static constexpr unsigned FIFO_SIZE = 3; // hardcoded size of the 6854 FIFO (this is a hardware limit) // internal state devcb_write_line m_out_irq_cb; /* interrupt request */ + devcb_write_line m_out_rdsr_cb; /* Rx fifo DMA request */ + devcb_write_line m_out_tdsr_cb; /* Tx fifo DMA request */ /* low-level, bit-based interface */ devcb_write_line m_out_txd_cb; /* transmit bit */ @@ -87,6 +93,8 @@ private: uint8_t m_rones; /* count '1 bits */ uint8_t m_rsize; /* bits in the shift register */ uint16_t m_rfifo[FIFO_SIZE]; /* X x 8-bit FIFO + full & addr marker bits */ + bool m_rxd; + bool m_rxc; /* frame-based interface*/ uint8_t m_frame[MAX_FRAME_LENGTH]; @@ -132,6 +140,7 @@ DECLARE_DEVICE_TYPE(MC6854, mc6854_device) The frame-based interface is higher-level and faster. It passes bytes directly from one end to the other without bothering with the actual bit-encoding, synchronization, and CRC. + Once completed, a frame is sent through out_frame. Aborted frames are not transmitted at all. No start flag, stop flag, or crc bits are transmitted. send_frame makes a frame available to the CPU through the 6854 (it may