Apple II Technical Notes _____________________________________________________________________________ Developer Technical Support SmartPort #8: SmartPort Packets Written by: Llew Roberts May 1989 This Technical Note describes the structure and timing of a sample SmartPort packet. _____________________________________________________________________________ SmartPort devices communicate using SmartPort packets. The following packet shows the timing and content of a SmartPort READBLOCK call. For further explanation of the structure, please see the Apple IIGS Hardware Reference and the Apple IIGS Firmware Reference. Note: The CPU will recognize and act on any packet put on the bus by a SmartPort Device. DATA MNEMONIC DESCRIPTION TIME (SmartPort Bus) (Relative) _____________________________________________________________________________ FF SYNC SELF SYNCHRONIZING BYTES 0 3F : : 32 micro Sec. CF : : 32 micro Sec. F3 : : 32 micro Sec. FC : : 32 micro Sec. FF : : 32 micro Sec. C3 PBEGIN MARKS BEGINNING OF PACKET 32 micro Sec. 81 DEST DESTINATION UNIT NUMBER 32 micro Sec. 80 SRC SOURCE UNIT NUMBER 32 micro Sec. 80 TYPE PACKET TYPE FIELD 32 micro Sec. 80 AUX PACKET AUXILLIARY TYPE FIELD 32 micro Sec. 80 STAT DATA STATUS FIELD 32 micro Sec. 82 ODDCNT ODD BYTES COUNT 32 micro Sec. 81 GRP7CNT GROUP OF 7 BYTES COUNT 32 micro Sec. 80 ODDMSB ODD BYTES MSB's 32 micro Sec. 81 COMMAND 1ST ODD BYTE = Command Byte 32 micro Sec. 83 PARMCNT 2ND ODD BYTE = Parameter Count 32 micro Sec. 80 GRP7MSB MSB's FOR 1ST GROUP OF 7 32 micro Sec. 80 G7BYTE1 BYTE 1 FOR 1ST GROUP OF 7 32 micro Sec. 98 G7BYTE2 BYTE 2 FOR 1ST GROUP OF 7 32 micro Sec. 82 G7BYTE3 BYTE 3 FOR 1ST GROUP OF 7 32 micro Sec. 80 G7BYTE4 BYTE 4 FOR 1ST GROUP OF 7 32 micro Sec. 80 G7BYTE5 BYTE 5 FOR 1ST GROUP OF 7 32 micro Sec. 80 G7BYTE5 BYTE 6 FOR 1ST GROUP OF 7 32 micro Sec. 80 G7BYTE6 BYTE 7 FOR 1ST GROUP OF 7 32 micro Sec. BB CHKSUM1 1ST BYTE OF CHECKSUM 32 micro Sec. EE CHKSUM2 2ND BYTE OF CHECKSUM 32 micro Sec. C8 PEND PACKET END BYTE 32 micro Sec. 00 FALSE FALSE IWM WRITE TO CLEAR REGISTER 32 micro Sec. _____________________________________________________________________________ Further Reference _____________________________________________________________________________ o Apple IIGS Hardware Reference o Apple IIGS Firmware Reference