MC68HC908SR12CFA Freescale Semiconductor, MC68HC908SR12CFA Datasheet - Page 168

• Manufacturer Part Number: MC68HC908SR12CFA
• Description: MICROCONTROLLER 48 PIN
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908SR12CFA

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: I²C, SCI
• Peripherals: LVD, POR, PWM, Temp Sensor
• Number Of I /o: 31
• Program Memory Size: 12KB (12K x 8)
• Program Memory Type: FLASH
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 14x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Other names: Q1145673

Monitor ROM (MON)
10.4.1 Entering Monitor Mode
Data Sheet
168
The monitor code allows enabling the PLL to generate the internal clock,
provided the reset vector is blank ($FF), when the device is being
clocked by a low-frequency crystal. This entry method, which is enabled
when IRQ1 is held low out of reset, is intended to support serial
communication/programming at 9600 baud in monitor mode by stepping
up the external frequency (assumed to be 32.768 kHz) by a fixed amount
to generate the desired internal frequency (2.4576 MHz).
If the reset vector is not blank (not $FF), the frequency stepping feature
is not supported, because IRQ1 cannot be held low for monitor mode
entry. With a non-blank reset vector, entry into monitor mode requires
V
Table 10-1
specified in the table, monitor mode may be entered after a POR and will
allow communication at 9600 baud provided one of the following sets of
conditions is met:
TST
1. If $FFFE and $FFFF do not contain $FF (programmed state):
2. If $FFFE and $FFFF both contain $FF (erased state):
3. If $FFFE and $FFFF both contain $FF (erased state):
on IRQ1.
– The external clock is 4.9152 MHz with PTC1 low or
– IRQ1 = V
– The external clock is 9.8304 MHz
– IRQ1 = V
– The external clock is 32.768 kHz (crystal)
– IRQ1 = V
9.8304 MHz with PTC1 high
IRQ1 pullup; PLL off)
32.768 kHz to an internal bus frequency of 2.4576 MHz)
shows the pin conditions for entering monitor mode. As
Monitor ROM (MON)
SS
TST
DD
(this setting initiates the PLL to boost the external
(this can be implemented through the internal
(PLL off)
MC68HC908SR12•MC68HC08SR12 — Rev. 5.0
Freescale Semiconductor