HD404019R Datasheet, PDF(43/65 Page) Renesas Technology Corp – CMOS 4-bit single-chip microcomputers

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HD404019R Datasheet, PDF (43/65 Pages) Renesas Technology Corp – CMOS 4-bit single-chip microcomputers

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HD404019R Series

Programmable ROM Operation

The on-chip PROM of HD4074019 and HD407L4019 are programmed in PROM mode. The PROM mode

is set by pulling TEST, M0, and M1 low, and RESET high as shown in figure 21. In PROM mode, the MCU

does not operate. It can be programmed like a standard 27256 EPROM using a standard PROM

programmer and a 64-to-28-pin socket adapter. Table 24 lists the recommended PROM programmers and

socket adapters.

Since the instruction of the HMCS400 series consists of 10 bits, the HMCS400-series microcom puter

incorporates a conversion circuit used as a general-purpose PROM programmer. By this circuit, an

instruction is read or programmed using 2 addresses, the low-order 5 bits and the high-order 5 bits. For

example, if 8 kwords of an on-chip PROM are programmed by a general purpose PROM programmer, 16

kbytes of addresses ($0000 to $3FFF) should be specified.

Programming and Verification

The HD4074019 and HD407L4019 can be programmed at high-speed without causing voltage stress or

affecting data reliability.

Table 23 shows how programming and verification modes are selected.

Erasing

PROMs with ceramic window packages can be erased by ultraviolet light. All erased bits become 1s.

The erasing specifications are as follows: ultraviolet (UV) light with wavelength 2537 Ã with a minimum

irradiation of 15 W sec/cm2. These conditions are satisfied by exposing the LSI to a 12,000-ÂµW/cm2 UV

source for 15 to 20 minutes at a distance of 1 inch.

Precautions

1. Addresses $0000 to $7FFF should be specified if the PROM is programmed by a PROM programmer.

Note that the plastic package type cannot be erased and reprogrammed.

(Only ceramic window packages can be erased and reprogrammed.)

2. Make sure that the PROM programmer, socket adapter, and LSI match properly. Using the wrong

programmer for the socket adapter may cause an overvoltage and damage the LSI. Make sure that the

LSI is firmly fixed in the socket adapter, and that the socket adapter is firmly fixed to the programmer.

3. The PROM should be programmed with VPP = 12.5 V. Other PROMs use 21 V. If 21 V is applied to the

HD4074019 and HD407L4019, the LSI may be permanently damaged. 12.5 V is the voltage for VPP of

Intelâs 27256.

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