UPD784938 Datasheet, PDF (562/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 23 INTERRUPT FUNCTIONS
There are four kinds of macro service, as shown below.
(1) Type A
One byte or one word of data is transferred between a special function register (SFR) and memory each time an interrupt
request is generated, and a vectored interrupt request is generated when the specified number of transfers have been
performed.
Memory that can be used in the transfers is limited to internal RAM addresses 0FE00H to 0FEFFH when the LOCATION
0 instruction is executed, and addresses 0FFE00H to 0FFEFFH when the LOCATION 0FH instruction is executed.
The specification method is simple and is suitable for low-volume, high-speed data transfers.
(2) Type B
As with type A, one byte or one word of data is transferred between a special function register (SFR) and memory each
time an interrupt request is generated, and a vectored interrupt request is generated when the specified number of
transfers have been performed.
The SFR and memory to be used in the transfers is specified by the macro service channel (the entire 1-Mbyte memory
space can be used).
This is a general version of type A, suitable for large volumes of transfer data.
(3) Type C
Data is transferred from memory to two special function registers (SFR) each time an interrupt request is generated,
and a vectored interrupt request is generated when the specified number of transfers have been performed.
With type C macro service, not only are data transfers performed to two locations in response to a single interrupt
request, but it is also possible to add output data ring control and a function that automatically adds data to a compare
register. The entire 1-Mbyte memory space can be used.
Type C is mainly used with the INTC10 and INTC11 interrupts, and is used for stepping motor control, etc., by macro
service, with P0L or P0H and CR10, CR10W, CR11, and CR11W used as the SFRs to which data is transferred.
(4) Counter mode
This mode is to decrement the macro service counter (MSC) when an interrupt occurs and is used to count the division
operation of an interrupt and interrupt generation circuit.
When MSC is 0, a vector interrupt can be generated.
To restart the macro service, MSC must be set again.
MSC is fixed to 16 bits and cannot be used as an 8-bit counter.
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Preliminary User’s Manual U13987EJ1V0UM00