MC68HC05SR3 Datasheet, PDF (89/96 Pages) Freescale Semiconductor, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcontroller Units

A.4.1 EPROM Programming
Programming boards are available from Freescale for programming the on-chip EPROM. Please
contact your Freescale Representative.
The Programming Control register (PCR) is provided for EPROM programming. The function of
the EPROM depends on the device operating mode.
A.4.2 Program Control Register (PCR)
Address bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
$0D
RESERVED
ELAT PGM ---- --00
ELAT - EPROM Latch Control
1 (set) –
0 (clear) –
EPROM address and data bus configured for programming (writes to
EPROM cause address data to be latched). EPROM is in
programming mode and cannot be read if ELATA is 1. This bit should
not be set unless a programming voltage is applied to the V_PP pin.
EPROM address and data bus configured for normal reads.
PGM - EPROM Program Command
1 (set) – Programming power connected to the EPROM array. If ELAT ≠ 1 then
PGM = 0.
0 (clear) – Programming power disconnected from the EPROM array.
A.4.3 EPROM Programming Sequence
Programming the EPROM of the MC68HC705SR3 is as follows:
1) Set the ELAT bit.
2) Write the data to be programmed to the address to be programmed.
3) Set the PGM bit.
4) Delay for 1ms.
5) Clear the PGM and the ELAT bits.
A
The last action may be carried out in a single CPU write operation. It is important to remember that
an external programming voltage must be applied to the V_PP pin while programming, but should
be equal to V_DD during normal operation.
Example shows address $1900 is programmed with $00.
MC68HC05SR3
MC68HC705SR3
TPG
Freescale
A-3