mitsubishi - Al Kossow's Bitsavers

MITSUBISHI MICROCOMPUTERSPCA8400MELPS 8-48 DEDICATED BOARDDESCRIPTIONThe PCA8400 is a dedicated MELPS 848 board for usewith the PC4000 debugging machine for the 8-bit singlechipmicrocomputers and is used by inserting the board inthe PC4000 cabinet.FEATURES• Connection to user's system by means of a 40-pin 01 Lplug• Control circuits and connectors for the i 8748 writingadaptor (PC41 00)APPLICATIONSThe development of hardware and software for systemsusing the MELPS 8-48 8-bit single-chip microcomputers.CONFIGURATIONAs can be seen in the block diagram, the PCA8400 consistsof the following hardware:(1) Evaluation chip (M5L8039P-6) and peripheral circuitry(2) ROM with the PC4000 monitor program(3) Single-step and breakpoint control circuit(4) Program memory interface circuit(5) Input/output buffer/latch circuitThe PC4000 is connected to this board using a cardedge connector and this board is connected to the usersystem by means of an accessory cable.FUNCTIONThe debugging machine PC4000 operates as a debuggingmachine for the MELPS 8-48 using the contents of themonitor ROM mounted on the ~dedicated board. Theevaluation chip (M5L8039P-6) loaded on the board executesthe program stored in the program memory in thePC4000 debugging machine.The internal status of the evalua~ion chip is read outunder monitor CPU control when single-step operation andbreakpoint operation are halted.An interface and connector to enable connection to theM5L8748S writing adaptor PC4100 has been provided,allowing programs to be written and read from thei8748.BLOCK DIAGRAMPORT DIRECTION ~--~--~ PORT DSWITCHING CIRCUITCOMPARISONADDRESSADDRESS LATCH8IE---------,~-~ PORT PlSINGLE-STEP'--------t--:.... CONTROL CIRCUITCLOCKGENERATOR4PORT SWITCHINGCIRCUITJPORT P2IADDRESSINSTRUCTIONDATA~IPC4000MONITOR ROMM5L2732KX 26 JM5L8155P..ITO PC4100M5L8748SWRITER- -i 8748 INTERFACE PORT---7-24 .•.. MITSUBISHI..... ELECTRIC