mitsubishi - Al Kossow's Bitsavers

MITSUBISHI MICROCOMPUTERSMSM80C49-XXXP/MSM80C39P-6SINGLE-CHIP a-BIT CMOS MICROCOMPUTERPIN DESCRIPTIONVssPinVee--STBYGroundNameMain power supplyStandbyTo Test pin 0Xl, X 2RESETCrystal inputsReset- SS Single stepĪNTEAInterruptExternal access- RO Read controlPSEN-WRALEProgram store enableWrite control0 0 -0 7 Data busP2o:""'P2 7 Port 2PROGPl o-P1 7TlAddress latch enableProgramPort ITest pin IInput or outputInputInputOutputInputInputInputInputInputOutputOutputOutputOutputInput/outputInput/outputOutputInput/outputOutputInput/outputInputNormally connected to ground (OV).Connected to 5V power supply.FunctionCDConnected t05V power supply during normal operation.~Used when entering the standby mode. Power dissipation is reduced by connecting this to OV.CDControl signal from an external source for conditional jumping in a program. Jumping is dependent onexternal conditions (JTO/JNTO).~Used for outputting the internal clock signal (ENTO CLK).External crystal oscillator or RC circuit input for generating internal clock signals.An external clock signal can be input through Xl or X2.Control used to initialize the CPU.Control signal used in conjunction with ALE to stop the CPU through each instruction, in the single-stepmode.CDControl signal from an external source for conditional jumping in a program. Jumping is dependent onexternal conditions (JNI).~Used for external interrupt to CPU.CDN ormally maintained at OV.~When the level is raised to 5V, external memory will be accessed even when the address is less than40016 (2048). The M5M80C39P is raised t05V.Read control signal used when the CPU requests data from external data memory or external device tobe transferred to the data bus.(MOVX A, @Rr, and INS A, BUS)Strobe signal to fetch external program memory.Write control signal used when the CPU sends data through the data bus to external data memory or externaldevice.(MOVX @Rr, A and OUTL BUS, A)A signal used for latching the address on the data bus. An ALE signal occurs once during each cycle.CDProvides true bidirectional bus transfer of instructions and data between the CPU and external memory.Synchronizing is done with signals RD/WR. The output data is latched.~When using external program memory, the output of the low-order 8 bits of the program counter aresynchronized with ALE. After that, the transfer of the instruction code or data from the external program--memory is synchronized with PSEN.@The output of addresses for data using the external data memory is synchronized with ALE. After that,the transfer of data with the external data: memory is synchronized with RD/WR.(MOVX A, @R r , and MOVX @R r , A)'CDQuasi-bidirectional port. When used as an input port, FF16 must first be output to this port. After reset,when not used as an output port, nothing needs to be output.~P20-P23 output high-order 4 bits of the program counter when using external program memory.@P20-P23 serve as a 4-bit I/O expander bus for the M5M82C43P.Strobe signal for M5M82C43P I/O expander.Quasi-bidirectional port. When used as an input port, FF16 must first be output to this port. After reset,when not used as an output port, nothing needs to be output.CDControl signal from an external source for conditional jumping in a program. Jumping is dependent onexternal conditions (JTI/JNTl).~When enabled, event signals are transferred to the timer/event counter (STRT CNT).II• MITSUBISHI"ELECTRIC4-45