HD404459 Datasheet, PDF (104/122 Pages) Renesas Technology Corp – 4-bit HMCS400-series microcomputers

HD404459 Series
Programming the Built-In PROM
The MCU’s built-in PROM is programmed in PROM mode. This PROM mode is set by pulling TEST, M₀,
and M₁ low, and RESET high (figure 83). In PROM mode, the MCU does not operate, but it can be
programmed in the same way as any other commercial 27256-type EPROM using a standard PROM
programmer and a 64-to-28-pin socket adapter. Refer to table 31 for the Recommended PROM
programmers and socket adapters of the HD4074459.
Since an HMCS400-series instruction is ten bits long, the HMCS400-series MCU has a built-in conversion
circuit to enable the use of a general-purpose PROM programmer. This circuit splits each instruction into
five lower bits and five upper bits that are read from or written to consecutive addresses. This means that if,
for example, 16 kwords of built-in PROM are to be programmed by a general-purpose PROM programmer,
a 32-kbyte address space ($0000–$7FFF) must be specified.
Warnings
1. Always specify addresses $0000 to $7FFF when programming with a PROM programmer. If address
$8000 or higher is accessed, the PROM may not be programmed or verified correctly. Set all data in
unused addresses to $FF.
Note that the plastic-package versions cannot be erased or reprogrammed.
2. Make sure that the PROM programmer, socket adapter, and LSI are aligned correctly (their pin 1
positions match), otherwise overcurrents may damage the LSI. Before starting programming, make sure
that the LSI is firmly fixed in the socket adapter and the socket adapter is firmly fixed onto the
programmer.
3. PROM programmers have two voltages (V_PP): 12.5 V and 21 V. Remember that ZTAT^TM devices
require a V_PP of 12.5 V—the 21-V setting will damage them. 12.5 V is the Intel 27256 setting.
Programming and Verification
The built-in PROM of the MCU can be program med at high speed without risk of voltage stress or damage
to data reliability.
Refer to table 30 for programming and verification modes.
For details of PROM programming, refer to the preface section, Notes on PROM Programming.
Table 30 PROM Mode Selection
Pin
Mode
CE
OE
V_PP
Programming
Low
High
V_PP
Verification
High
Low
V_PP
Programming inhibited
High
High
V_PP
O₀–O₇
Data input
Data output
High impedance
102