HD64F2638F20J Renesas Electronics America, HD64F2638F20J Datasheet - Page 236

• Manufacturer Part Number: HD64F2638F20J
• Description: IC H8S MCU FLASH 256K 128-QFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8S/2600r

Specifications of HD64F2638F20J

• Core Processor: H8S/2600
• Core Size: 16-Bit
• Speed: 20MHz
• Connectivity: CAN, SCI, SmartCard
• Peripherals: Motor Control PWM, POR, PWM, WDT
• Number Of I /o: 72
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 12x10b; D/A 2x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 128-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

Section 7 Bus Controller
7.7
The chip has a write data buffer function in the external data bus. Using this function enables the
write data buffer to be accessed in parallel. The write data buffer function is made available by
setting the WDBE bit in BCRL to 1.
Figure 7-18 shows an example of the timing when the write data buffer function is used. When
this function is used, if an external write continues for 2 states or longer, and there is an internal
access next, only an external write is executed in the first state, but from the next state onward an
internal access (on-chip memory or internal I/O register read/write) is executed in parallel with the
external write rather than waiting until it ends.
Page 186 of 1458
External
space
write
Internal address bus
Internal read signal
Figure 7-18 Example of Timing when Write Data Buffer Function Is Used
Write Data Buffer Function
HWR, LWR
D15 to D0
A23 to A0
φ
T
1
On-chip memory read Internal I/O register read
T
Internal memory
2
External write cycle
External address
T
W
Internal I/O register address
T
H8S/2639, H8S/2638, H8S/2636,
W
REJ09B0103-0800 Rev. 8.00
H8S/2630, H8S/2635 Group
T
3
May 28, 2010