DF2437FV Renesas Electronics America, DF2437FV Datasheet - Page 312

• Manufacturer Part Number: DF2437FV
• Description: IC H8S/2437 MCU FLASH 128QFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8S/2400r

Specifications of DF2437FV

• Core Processor: H8S/2600
• Core Size: 16-Bit
• Speed: 20MHz
• Connectivity: I²C, SCI
• Peripherals: POR, PWM, WDT
• Number Of I /o: 85
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Data Converters: A/D 16x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 128-QFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

10.7.4
When the internal clock is changed, the changeover may cause FRC to be incremented. This
depends on the timing at which the clock is switched (bits CKS1 and CKS0 are rewritten). Table
10.3 shows the relationship between the timing and the FRC operation.
When an internal clock is used, the FRC clock is generated on detection of the falling edge of the
internal clock scaled from the system clock (φ). If the clock is changed when the old source is high
and the new source is low, as in case no. 3 in table 10.3, the changeover is regarded as a falling
edge that triggers the FRC clock, and FRC is incremented. Switching between an internal clock
and external clock can also cause FRC to be incremented.
Rev.2.00 May. 28, 2009 Page 272 of 732
REJ09B0059-0200
Figure 10.20 Conflict between OCRAR/OCRAF Write and Compare-Match
Switching of Internal Clock and FRC Operation
Compare-match signal
Internal write signal
OCRAR (OCRAF)
(When Automatic Addition Function is Used)
Address
OCR
FRC
φ
Automatic addition is not performed
because compare-match signals are disabled.
OCRAR (OCRAF)
address
Disabled
Old data
N
N
New data
N+1