Command Pass Through Register (CPTR)
VMEbus Address: Base Address + 11B (hex)
Attributes: Read Only, Internal to TLC
R
7 654 3210
CPT7 CPT6 CPT5 CPT4 CPT3 CPT2 CPT1 CPT0
Bit Mnemonic Description
7-0r CPT[7-0] Command Pass Through Bits 7 through 0
These bits are used to transfer undefined multiline GPIB command
messages from the GPIB DIO lines to the computer. When the CPT
feature is enabled (CPT ENABLE=1, AUXRB[0]w), any GPIB
Primary Command Group (PCG) message not decoded by the TLC is
treated as an undefined command. The multiline GPIB commands
recognized by the µPD7210 are listed in Table 4-3. All GPIB
Secondary Command Group (SCG) messages following an undefined
GPIB PCG message are also treated as undefined. When an undefined
GPIB message is encountered, it is held in the CPTR and the TLC
Acceptor Handshake function is held off (in ACDS) until the Valid
auxiliary command is written to the AUXMR. The CPTR is also used
to inspect secondary addresses when mode 3 addressing is used. The
TLC Acceptor Handshake function is held off (in ACDS) until the
Valid or Non-Valid auxiliary command is written to the AUXMR.
Table 4-3. Multiline GPIB Commands Recognized by the µPD7210
Hex Number Message Description
01 GTL Go To Local
04 SDC Selected Device Clear
05 PPC Parallel Poll Configure
08 GET Group Execute Trigger
09 TCT Take Control
11 LLO Local Lockout
14 DCL Device Clear
(continues)