UPD784915B Datasheet, PDF (53/86 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784915B, 784916B
(3) Macro service type A
When an interrupt request occurs, data is transferred from an 8-/16-bit SFR to memory (byte/word) or from
memory (byte/word) to an 8-/16-bit SFR.
Data is transferred the number of times set in advance by the macro service counter.
This mode can be used to store the result of A/D conversion or for automatic transfer (or reception) by the serial
interface.
Because transfer data is stored at an address FE00H to FEFFH, if only a small quantity of data is to be transferred,
the data can be transferred at high speeds.
When the value of the macro service counter is decremented to 0, a vector interrupt request occurs.
Data storage buffer (memory)
Data n
Data n - 1
Data storage buffer (memory)
Data n
Data n - 1
Data 2
Data 1
Data 2
Data 1
Internal bus
Internal bus
SFR
SFR
(4) Data pattern identification mode (VISS detection mode)
This mode of macro service is for detection of the VISS signal and is used in combination with a pulse width
detection circuit.
When an interrupt request occurs, the content of bit 7 of an SFR (usually, TMC3) specified by SFR pointer 1 is
shifted into the buffer area. At the same time, the data in the buffer area is compared with the data in the compare
area. If the two data coincide, an interrupt request is generated. When the value of the macro service counter
is decremented to 0, a vector interrupt request occurs.
It can be specified by option that the value of an SFR (usually, CPT30) specified by SFR pointer 2 be multiplied
by a coefficient and the result of this multiplication be stored to an SFR (usually, CR30) specified by SFR pointer
3 (this operation is to automatically update an identification threshold value when the tape speed fluctuates).
Coefficient (memory)
Multiplier
CPT30
TM3
CR30
Buffer area (memory) Compare area (memory)
CTL F/F
(bit 7 of TMC3)
Coincidence
Vector interrupt
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