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T
PHPL
T
PHIL
T
ILIH
T
ILVH
T
ILPL
T
PHVL
15.9 AUTO PROGRAMMING MODE
The auto programming mode is a low-cost programming alternative. Using this programming
mode, the device programs itself with data from an external EPROM (external locations 4000H
and above; see Table 15-1 on page 15-2). A bank switching mechanism supplied by P1.2 and P1.1
supports auto programming of devices with more than 16 Kbytes of internal memory.
15.9.1 Auto Programming Circuit and Memory Map
Figure 15-12 shows the recommended circuit and Table 15-10 shows the memory map for auto
programming mode. Auto programming is specified for a crystal frequency of 6 to 8 MHz. At 8
MHz, use a 27(C)512 EPROM with tACC = 250 ns and tOE = 100 ns or faster specifications.
Tie the BUSWIDTH pin low to configure an 8-bit data bus. Connect P1.1 and P1.2 as shown to
generate the high-order bits of the external EPROM address. Connect P0.7:4 to V
select auto programming (1100B = 0CH). PACT# and PVER are status outputs, buffered by the
74HC14s. They drive LEDs that indicate programming active (PACT#) and programming verifi-
cation (PVER). Connect all unused inputs to ground (V
READY and NMI are active; connect them as indicated.
All external EPROM addresses specified in this section are given for the
circuit in Figure 15-12. If you choose a different circuit, you must adjust the
addresses accordingly.
Table 15-9. Timing Mnemonics (Continued)
Mnemonic
PROG# High to Next PROG# Low.
PROG# High to AINC# Low.
AINC# Pulse Width.
PVER Hold After AINC# Low.
AINC# Low to PROG# Low.
PROG# High to PVER Valid.
NOTE
PROGRAMMING THE NONVOLATILE MEMORY
Description
) and leave unused outputs floating.
SS
and V
to
SS
CC
15-25
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