Apple II
Technical Notes
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                                                  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.
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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)
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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.
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Further Reference
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    o    Apple IIGS Hardware Reference
    o    Apple IIGS Firmware Reference
