[NTLK] Random findings on hardware registers

[Matthias Melcher]

To the hackers on the list:

I have been working on implementing the hardware emulation in Einstein that we need to get the external serial port working for the emulation. With a bit of luck, we will be able to use NCX and all the other programs to connect to Einstein running on the same or even another machine.

The good news: I am able to send and receive data!

The snot so good news: I have very little time to convert this from a hack into a stable interface, but I will continue to work on it.


In relation to the other thread in which we try to find the documentation, here are my findings:

Additions and corrections are very welcome!


 Serial Port Hardware Reverse Engineering
 
 TSerialChipVoyager : TSerialChip : TProtocol
 ============================================

     +36    0x24: HW Base Address
     +56    0x38: Recieve buffer size
    +100    0x64: bit 7: set if Tx Buffer is full
    +116    0x74: Rx: TSerialDMAEngine
    +136    0x88: TCircleBuf Rx
    +143    0x8F: b: 02 to handle rx int
    +144    0x90: w:


 Serial port registers starting at 0x0F1C0000
 ============================================

? kSerReg_BreakDuplex	= 0x2400,

    0000:  w 40
    0400:  w 06
    0800:  w 00
    0C00:  w 02
    1000:  w 00
    2000:  w 62 (EnableRxDMA writes 62)
                bit 1: write: Clear Rx Error Status?
    2400: rw 25 (EnableTxDMA)
                bit 0: TxDMAEnable
    2800:  w 23 (SetTxDTransceiverEnable writes 23)
                bit 1: write: set outputs? DTR, RTS?
    3000: rw F9 (SetInterruptEnable writes F9) some interrupt status mask?
    3400:  w F9
    3800:  w 19
    3C00:  w 40 (SetIntSourceEnable(0x00000040, 1) writes 40)
                bit 7: write: Tx Buffer is empty
    4400:  r 00 
                bit 7: read:  Tx Buffer is empty
                bit 6: read:  Rx Buffer is full
                bit 5: read:  Rx Byte available?
                bit 4: read:  DCD asserted
                bit 3: read:  CTS asserted
                bit 2: read:  Tx underrun (also in 3000)
                bit 0: read:  Serial abort (also in 3000)
    4800:  r 00
                bit 7, 6, 5, 4: read:  Rx Error Status
    5000:  w 00
    5400:  w 02
    5800: r  00
    5C00: r  00
    6000:       tx byte buffer (non-DMA)
    7000:       rx byte buffer (non-DAM)
    8000:  w 00


 
 Serial port DMA
 ===============
 
    Address   Bank, Channel, Register
        Receive:
    F080000 = 1,0,0:  w: rx physical buffer address (InitRxDMA)
    F080400 = 1,0,1:  w: current buffer address? (RxDMAControl)
    F080800 = 1,0,2
    F080C00 = 1,0,3:  w: 00000080 (RxDMAControl), 00000000
    F081000 = 1,0,4: rw: 00000403 buffer count? (RxDMAControl) (reading when shutting down?)
    F081400 = 1,0,5:  w: 00000404 buffer size? (RxDMAControl)
    F081800 = 1,0,6:  w: 00000000 (InitRxDMA), 000000FF (RxDMAControl)
    F090000 = 2,0,0:  w: 00000006 (RxDMAControl), 00000000
    F090400 = 2,0,1: r : (RxDMAControl)
    F090800 = 2,0,2:  w: 00000000 (RxDMAControl)
    F090C00 = 2,0,3:  w: 00000006 (InitRxDMA)
        Transmit:
    F082000 = 1,1,0:  w: tx physical buffer address (InitTxDMA)
    F082400 = 1,1,1: rw: current buffer address? (TxDMAControl)
    F082800 = 1,1,2
    F082C00 = 1,1,3:  w: 000000C0 (TxDMAControl)
    F083000 = 1,1,4: rw: number of bytes to write (TxDMAControl)
    F083400 = 1,1,5:  w: 204, buffer size? (TxDMAControl)
    F083800 = 1,1,6:  w: 00000000 (InitTxDMA)
    F091000 = 2,1,0:  w: 00000002 (TxDMAControl)
    F091400 = 2,1,1: r : (TxDMAControl)
    F091800 = 2,1,2:  w: 00000000 (TxDMAControl)
    F091C00 = 2,1,3:  w: 00000002 (InitTxDMA)

    AssignmentRegister:     InitByOption is setting bit 2
    EnableRegister:      w: 00000001, 00000002 (RxDMAControl) // Bits set to 1 will start the DMA transfers.
    StatusRegister:         Bits set to 1 indicate pending dma transfers.
    DisableRegister:     w: 00000001, 00000002 // Bits set to 1 will abort the DMA transfers.
    WordStatusRegister: r : Bits set to 1 indicate words in channel word registers.


 Serial port interrupts
 ======================

 kDMAChannel0IntMask	= 0x00000080,						// Serial port 0 rcv
 kDMAChannel1IntMask	= 0x00000100,						// Serial port 0 tx

Which register holds the values below?
 typedef ULong SerialIntSource;	// matches Voyager interrupt mask reg bits
 #define kSerIntSrcAbort		(0x00000001)	// break or abort
 #define kSerIntSrcHunt			(0x00000002)
 #define kSerIntSrcUnderRun		(0x00000004)
 #define kSerIntSrcCTS			(0x00000008)
 #define kSerIntSrcDCD			(0x00000010)
 #define kSerIntSrcRxSpecial		(0x00000020)
 #define kSerIntSrcRxOnAllChars		(0x00000040)
 #define kSerIntSrcTxBufEmpty		(0x00000080)
 #define kSerIntSrcRxOnFirstChar	(0x00000100)	// may go away