DF2328BVF25V Renesas Electronics America, DF2328BVF25V Datasheet - Page 242

• Manufacturer Part Number: DF2328BVF25V
• Description: IC H8S MCU FLASH 256K 128QFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8S/2300r

Specifications of DF2328BVF25V

• Core Processor: H8S/2000
• Core Size: 16-Bit
• Speed: 25MHz
• Connectivity: SCI, SmartCard
• Peripherals: DMA, POR, PWM, WDT
• Number Of I /o: 87
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 8K 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
• For Use With: EDK2329 - DEV EVALUATION KIT H8S/2329
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Other names: HD64F2328BVF25V

Section 6 Bus Controller
6.10
6.10.1
The chip can release the external bus in response to a bus request from an external device. In the
external bus released state, the internal bus master continues to operate as long as there is no
external access.
If an internal bus master wants to make an external access in the external bus released state, or if a
refresh request * is generated, it can issue a bus request off-chip.
The BREQOPS bit can be used to change the BREQO output pin from PF
Note: * The DRAM interface is not supported in the H8S/2321.
6.10.2
In external expansion mode, the bus can be released to an external device by setting the BRLE bit
in BCRL to 1. Driving the BREQ pin low issues an external bus request to the chip. When the
BREQ pin is sampled, at the prescribed timing the BACK pin is driven low, and the address bus,
data bus, and bus control signals are placed in the high-impedance state, establishing the external
bus released state.
In the external bus released state, an internal bus master can perform accesses using the internal
bus. When an internal bus master wants to make an external access, it temporarily defers
activation of the bus cycle, and waits for the bus request from the external bus master to be
dropped. Even if a refresh request * is generated in the external bus released state, refresh control *
is deferred until the external bus master drops the bus request.
If the BREQOE bit in BCRL is set to 1, when an internal bus master wants to make an external
access in the external bus released state, or when a refresh request * is generated, the BREQO pin
is driven low and a request can be made off-chip to drop the bus request.
When the BREQ pin is driven high, the BACK pin is driven high at the prescribed timing and the
external bus released state is terminated.
If an external bus release request and external access occur simultaneously, the order of priority is
as follows:
Rev.6.00 Sep. 27, 2007 Page 210 of 1268
REJ09B0220-0600
Bus Release
Overview
Operation
(High) External bus release > Internal bus master external access (Low)
2
to P5
3
.