UPD17217CT-XXX View Datasheet(PDF) - NEC => Renesas Technology

Part Name

Description

Manufacturer

UPD17217CT-XXX

4-BIT SINGLE-CHIP MICROCONTROLLER FOR SMALL GENERAL-PURPOSE INFRARED REMOTE CONTROL TRANSMITTER

NEC => Renesas Technology 

µPD17215, 17216, 17217, 17218

2.5.2 Control registers

The control registers consists of a total of 64 nibbles (64 x 4 bits) of the addresses 00H-3FH of the register file.

Of these, however, only 14 nibbles are actually used. The remaining 50 nibbles are unused registers that are inhibited

from being read or written.

When the “PEEK WR, rf” instruction is executed, the contents of the register file addressed by “rf” are read to the window

register.

When the “POKE rf, WR” instruction is executed, the contents of the window register are written to the register file

addressed by “rf”.

When using the assembler (AS17K), the macro instructions listed below, which are embedded as flag type symbol

manipulation instructions, can be used. The macro instructions allow the contents of the register file to be manipulated in

bit units.

For the configuration of the control register, refer to Fig. 11-1 Register File List.

SETn : Sets flag to “1”

CLRn : Sets flag to “0”

SKTn : Skips if all flags are “1”

SKFn : Skips if all flags are “0”

NOTn : Complements flag

INITFLG: Initializes flag

2.5.3 Notes on using register files

When using the register files, bear in mind the points described below. For details, refer to µPD172xx subseries User’s

Manual (IEU-1317).

(1) When manipulating control registers (read-only and unused registers)

When manipulating the write-only (W), the read-only (R) and unused control registers by using the assembler

or in-circuit emulator, keep in mind the following points:

• When device operates

Nothing changes even if data is written to the read-only register.

If the unused register is read, an undefined value is read; nothing is changed even if data is written to this

register.

• Using assembler

An error occurs if instruction is excecuted to read data to the write-only register.

An error occurs if an instruction is executed to write data to the read-only register.

An error also occurs if an instruction is executed to read or write the unused address.

• When an in-circuit emulator (IE-17K or IE-17K-ET) is used (when instruction is executed for patch

processing)

An undefined value is read if the write-only register is read, and an error does not occur.

Nothing changes even if data is written to the read-only register, and an error does not occur.

An undefined value is read if the unused address is read; nothing changes even if data is written to this

address. An error does not occur.

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