MC908QY4ACDWE Freescale Semiconductor, MC908QY4ACDWE Datasheet - Page 96

• Manufacturer Part Number: MC908QY4ACDWE
• Description: IC MCU 8BIT 4K FLASH 16-SOIC
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC908QY4ACDWE

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Peripherals: LVD, POR, PWM
• Number Of I /o: 13
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 6x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 16-SOIC (0.300", 7.5mm Width)
• Processor Series: HC08QY
• Core: HC08
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 13
• Number Of Timers: 2
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Development Tools By Supplier: FSICEBASE, M68CBL05AE, DEMO908QB8, DEMO908QC16
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 6 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Connectivity: -
• Lead Free Status / Rohs Status: Details

Oscillator (OSC) Module
copy the trim value from $FFC0 or $FFC1 into OSCTRIM if needed. The factory trim value provides the
accuracy required for communication using forced monitor mode. Some production programmers erase
the factory trim values, so confirm with your programmer vendor that the trim values at $FFC0 and $FFC1
are preserved, or are re-trimmed. Trimming the device in the user application board will provide the most
accurate trim value.
11.3.2.2 Internal to External Clock Switching
When external clock source (external OSC, RC, or XTAL) is desired, the user must perform the following
steps:
After ECGON set is detected, the OSC module checks for oscillator activity by waiting two external clock
rising edges. The OSC module then switches to the external clock. Logic provides a coherent transition.
The OSC module first sets ECGST and then stops the internal oscillator.
11.3.2.3 External to Internal Clock Switching
After following the procedures to switch to an external clock source, it is possible to go back to the internal
source. By clearing the OSCOPT[1:0] bits and clearing the ECGON bit, the external circuit will be
disengaged. The bus clock will be derived from the selected internal clock source based on the ICFS[1:0]
bits.
11.3.3 External Oscillator
The external oscillator option is designed for use when a clock signal is available in the application to
provide a clock source to the MCU. The OSC1 pin is enabled as an input by the oscillator module. The
clock signal is used directly to create BUSCLKX4 and also divided by two to create BUSCLKX2.
In this configuration, the OSC2 pin cannot output BUSCLKX4. The OSC2EN bit will be forced clear to
enable alternative functions on the pin.
11.3.4 XTAL Oscillator
The XTAL oscillator circuit is designed for use with an external crystal or ceramic resonator to provide an
accurate clock source. In this configuration, the OSC2 pin is dedicated to the external crystal circuit. The
OSC2EN bit has no effect when this clock mode is selected.
In its typical configuration, the XTAL oscillator is connected in a Pierce oscillator configuration, as shown
in
represent actual circuitry.
96
Figure
1. For external crystal circuits only, configure OSCOPT[1:0] to external crystal. To help precharge an
2. Configure OSCOPT[1:0] and ECFS[1:0] according to
3. Create a software delay to provide the stabilization time required for the selected clock source
4. After the stabilization delay has elapsed, set ECGON.
external crystal oscillator, momentarily configure OSC2 as an output and drive it high for several
cycles. This can help the crystal circuit start more robustly.
The oscillator module control logic will then enable OSC1 as an external clock input and, if the
external crystal option is selected, OSC2 will also be enabled as the clock output. If RC oscillator
option is selected, enabling the OSC2 output may change the bus frequency.
(crystal, resonator, RC). A good rule of thumb for crystal oscillators is to wait 4096 cycles of the
crystal frequency; i.e., for a 4-MHz crystal, wait approximately 1 ms.
11-2. This figure shows only the logical representation of the internal components and may not
MC68HC908QYA/QTA Family Data Sheet, Rev. 3
11.8.1 Oscillator Status and Control
Freescale Semiconductor
Register.