Application Note
AN1060 — Rev. 1.0
230
MOTOROLA
R14–Rl5. The PE7 input was chosen because the internal circuitry for
port E pins can tolerate voltages slightly higher than V
DD
; therefore,
resistors R14 and R15 are less critical. No data to be programmed is
passed to the target MCU until the master MCU senses that V
PP
has
been stable for about 200 ms.
When V
PP
is ready, the master MCU turns on the red LED (light-emitting
diode) and begins passing data to the target MCU.
EPROM
Programming Utility
explains the activity as data is sent from the
master MCU to the target MCU and programmed into the EPROM of the
target. The master MCU in the EVBU corresponds to the HOST in the
programming utility description and the "PROGRAM utility in MCU" is
running in the bootstrap ROM of the target MCU.
Each byte of data sent to the target is programmed and then the
programmed location is read and sent back to the master for verification.
If any byte fails, the red and green LEDs are turned off, and the
programming operation is aborted. If the entire 12 Kbytes are
programmed and verified successfully, the red LED is turned off, and the
green LED is turned on to indicate success. The programming of all 12
Kbytes takes about 30 seconds.
After a programming operation, the V
PP
switch (S2) should be turned off
before the EVBU power is turned off.
Figure 7. Isolating EVBU XIRQ Pin
25
13
1
1
1
3
+
9
8
10
20
21
19
15
7
1
2
45
4847
46
44
41
38
34
3533
27
28
4
5
CUT TRACE
AS SHOWN
RN1D
47K
VDD
J14
J7
TO
MC68HC68T1
REMOVE J7
JUMPER
BE SURE NO
JUMPER IS
ON J14
FROM OC5 PIN
OF MCU
TO MCU
PIN
P4-18
P5-18
XIRQ/V
PPE
F
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
.