4.5 KiB
4.5 KiB
Description
BMac aka BigMac is an Ethernet media access controller cell integrated in the Heathrow and Paddington I/O controllers. According to a former Apple employee, BMac has been licensed from Sun. It's therefore not surprising that it has a lot in common with the Sun "Happy Meal" (HME) controller.
BMac based Ethernet HW
There are three BMac based HW configurations:
- BMac in a Heathrow I/O + LXT907 PHY used in Power Macintosh G3 (Old World)
- BMac+ in a Paddington I/O + LXT970 aka ST10040 PHY in Power Macintosh Blue & White (New World)
- BMac+ in a Paddington I/O + DP83843 PHY in a Bronze Keyboard PowerBook G3
Documentation
No official documentation has surfaced so far. Fortunately, the official source code as well as the STP2002 datasheet provide enough information on the BMac device.
- Apple source code: https://github.com/apple-oss-distributions/AppleBMacEthernet
- STP2002 datasheet: https://people.freebsd.org/~wpaul/STP2002QFP-UG.pdf
Register Map
BMac registers are located at offset 0x11000 starting from the I/O controller base address.
| Register Name | Offset | Description |
|---|---|---|
| XIFC | 0x000 | Transceiver interface configuration register |
| TXFIFOCSR | 0x100 | Transceiver FIFO control & status register |
| TXTH | 0x110 | Transceiver FIFO treshold |
| RXFIFOCSR | 0x120 | Receiver FIFO control & status register |
| MEMADD | 0x130 | |
| XCVRIF | 0x160 | |
| CHIPID | 0x170 | Chip aka Ethernet cell identification register |
| MIFCSR | 0x180 | Media interface control & status register |
| SROMCSR | 0x190 | Serial EEPROM control & status register |
| TXPNTR | 0x1A0 | Transceiver pointer |
| RXPNTR | 0x1B0 | Receiver pointer |
| STATUS | 0x200 | Global status register |
| INTDISABLE | 0x210 | Global interrupt disable register |
| TXRST | 0x420 | Transceiver software reset |
| TXCFG | 0x430 | Transceiver configuration register |
| IPG1 | 0x440 | Interpacket gap 1 register |
| IPG2 | 0x450 | Interpacket gap 2 register |
| ALIMIT | 0x460 | Transceiver attempt limit register |
| SLOT | 0x470 | Transceiver slot time register |
| PALEN | 0x480 | Transceiver preamble length register |
| PAPAT | 0x490 | Transceiver preamble pattern register |
| TXSFD | 0x4A0 | Transceiver start of frame delimiter (SFD) register |
| JAM | 0x4B0 | Transceiver jam size register |
| TXMAX | 0x4C0 | Transceiver maximum frame size register |
| TXMIN | 0x4D0 | Transceiver minimum frame size register |
| PAREG | 0x4E0 | Transceiver peak attempts register |
| DCNT | 0x4F0 | Defer timer (counter ?) |
| NCCNT | 0x500 | Normal collision counter |
| NTCNT | 0x510 | Network collision counter |
| EXCNT | 0x520 | Excessive collision counter |
| LTCNT | 0x530 | Late collision counter |
| RSEED | 0x540 | Transceiver random number seed register |
| TXSM | 0x550 | Transceiver state machine register |
| RXRST | 0x620 | Receiver software reset register |
| RXCFG | 0x630 | Receiver configuration register |
| RXMAX | 0x640 | Receiver maximum frame size register |
| RXMIN | 0x650 | Receiver minimum frame size register |
| MADD2 | 0x660 | Receiver MAC address 2 register |
| MADD1 | 0x670 | Receiver MAC address 1 register |
| MADD0 | 0x680 | Receiver MAC address 0 register |
| FRCNT | 0x690 | Receiver frame counter register |
| LECNT | 0x6A0 | Receiver length error counter register |
| AECNT | 0x6B0 | Receiver alignment error counter register |
| FECNT | 0x6C0 | Receiver frame check sum error counter register |
| RXSM | 0x6D0 | Receiver state machine register |
| RXCV | 0x6E0 | Receiver code violation register |
| HASH3 | 0x700 | Receiver hash table 3 register |
| HASH2 | 0x710 | Receiver hash table 2 register |
| HASH1 | 0x720 | Receiver hash table 1 register |
| HASH0 | 0x730 | Receiver hash table 0 register |
| AFR2 | 0x740 | Receiver address filter 2 register |
| AFR1 | 0x750 | Receiver address filter 1 register |
| AFR0 | 0x760 | Receiver address filter 0 register |
| AFCR | 0x770 | Receiver address filter control register |