MC68HC711D3_05 Datasheet, PDF (32/138 Pages) Freescale Semiconductor, Inc – Microcontrollers

Operating Modes and Memory
2.4.2 Programming the EPROM with Downloaded Data
When using this method, the EPROM is programmed by software while in the special test or bootstrap
modes. User-developed software can be uploaded through the SCI or a ROM-resident EPROM
programming utility can be used. The 12-volt nominal programming voltage must be present on the
XIRQ/V_PP pin. To use the resident utility, bootload a 3-byte program consisting of a single jump instruction
to $BF00. $BF00 is the starting address of a resident EPROM programming utility. The utility program
sets the X and Y index registers to default values, then receives programming data from an external host,
and puts it in EPROM. The value in IX determines programming delay time. The value in IY is a pointer
to the first address in EPROM to be programmed (default = $F000).
When the utility program is ready to receive programming data, it sends the host the $FF character. Then
it waits. When the host sees the $FF character, the EPROM programming data is sent, starting with the
first location in the EPROM array. After the last byte to be programmed is sent and the corresponding
verification data is returned, the programming operation is terminated by resetting the MCU.
2.4.3 PROM Programming Control Register
The PROM programming control register (PPROG) is used to control the programming of the OTPROM
or EPROM. PPROG is cleared on reset so that the PROM is configured for normal read.
Address: $003B
Bit 7
6
5
4
3
2
1
Bit 0
Read:
MBE
0
ELAT EXCOL EXROW
0
Write:
Reset: 0
0
0
0
0
0
0
PGM
0
0
Figure 2-5. PROM Programming Control Register (PPROG)
MBE — Multiple Byte Program Enable Bit
This bit is reserved for testing.
Bit 6, 2, and 1 — Not implemented
Always read 0.
ELAT — EPROM (OTPROM) Latch Control Bit
1 = PROM address and data bus are configured for programming. Writes to PROM cause address
and data to be latched. The PROM cannot be read.
0 = PROM address and data bus are configured for normal reads. PROM cannot be programmed.
EXCOL — Select Extra Columns Bit
This bit is reserved for testing.
EXROW — Select Extra Row Bit
This bit is reserved for testing.
PGM — EPROM (OTPROM) Program Command Bit
This bit may be written only when ELAT = 1.
1 = Programming power is switched on to PROM array.
0 = Programming power is switched off.
MC68HC711D3 Data Sheet, Rev. 2.1
32
Freescale Semiconductor