D12321VF20V Renesas Electronics America, D12321VF20V Datasheet - Page 236

• Manufacturer Part Number: D12321VF20V
• Description: IC H8S/2321 MCU ROMLESS 128QFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8S/2300r

Specifications of D12321VF20V

• Core Processor: H8S/2000
• Core Size: 16-Bit
• Speed: 20MHz
• Connectivity: SCI, SmartCard
• Peripherals: POR, PWM, WDT
• Number Of I /o: 86
• Program Memory Type: ROMless
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 8x10b; D/A 2x8b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 128-QFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -

Section 6 Bus Controller
Write after Read: If an external write occurs after an external read while the ICIS0 bit in BCRH
is set to 1, an idle cycle is inserted at the start of the write cycle.
Figure 6.32 shows an example of the operation in this case. In this example, bus cycle A is a read
cycle from ROM with a long output floating time, and bus cycle B is a CPU write cycle. In (a), an
idle cycle is not inserted, and a collision occurs in cycle B between the read data from ROM and
the CPU write data. In (b), an idle cycle is inserted, and a data collision is prevented.
Rev.6.00 Sep. 27, 2007 Page 204 of 1268
REJ09B0220-0600
Address bus
CS (area A)
CS (area B)
Data bus
HWR
RD
φ
(a) Idle cycle not inserted
T
1
Bus cycle A
(ICIS0 = 0)
T
2
Figure 6.32 Example of Idle Cycle Operation (2)
T
floating time
Long output
3
Bus cycle B
T
1
T
2
Data
collision
Address bus
CS (area A)
CS (area B)
Data bus
HWR
RD
φ
T
(b) Idle cycle inserted
1
Bus cycle A
(ICIS0 = 1 (initial value))
T
2
T
3
T
I
Bus cycle B
T
1
T
2