MC68HC908JB8 Datasheet, PDF (165/286 Pages) Motorola, Inc – MICROCONTROLLERS

Monitor ROM (MON)
Functional Description
V_DD
V_DD + V_HI
10k Ω
10k Ω
(SEE NOTE 2)
C
SW2
0.1 µF
1
+
10 µF
3
4
10 µF
+2
DB-25
2
5
3
6
7
MC145407
D
V_DD
6 MHz
+
4.7 µF
0.1 µF
V_DD
(SEE NOTE 3)
0.1 µF
20
+
10 µF
18
6 MHz
20 pF
E _SW3
F
E
f_XCLK
17
10 µF ^VDD
19 ⁺
16
15
F
20 pF
3.3 V
10 kΩ
A
(SEE NOTE 1) _B
SW1
3.3 V
1
14
MC74LCX125
2
3
6
5
3.3 V
10 kΩ
4
3.3 V
10 kΩ
7
NOTES:
1. Affects high voltage entry to monitor mode only (SW2 at position C):
SW1: Position A — Bus clock = f_XCLK ÷ 2
SW1: Position B — Bus clock = f_XCLK
2. SW2: Position C — High-voltage entry to monitor mode.
SW2: Position D — Low-voltage entry to monitor mode (with blank reset vector).
See Section 18 for IRQ voltage level requirements.
3. SW3: Position E — OSC1 directly driven by external oscillator.
SW3: Position F — OSC1 driven by crystal oscillator circuit.
10 kΩ
RST
HC908JB8
IRQ
V_REG
V_DD
V_SS
OSC1
OSC2
PTA3
PTA0
PTA1
PTA2
Figure 10-1. Monitor Mode Circuit
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Freescale Semiconductor
Monitor ROM (MON)
Technical Data
165