M37702E6BFS Renesas Electronics America, M37702E6BFS Datasheet - Page 42

• Manufacturer Part Number: M37702E6BFS
• Description: EPROM MCU/8BIT CMOS EMULATION CH
• Manufacturer: Renesas Electronics America

Specifications of M37702E6BFS

• Accessory Type: Emulator EPROM MCU
• For Use With/related Products: 7702
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

CENTRAL PROCESSING UNIT (CPU)
2.2 Bus interface unit
2–14
2.2.3 Operation of bus interface unit (BIU)
Figure 2.2.3 shows the basic operating waveforms of the bus interface unit (BIU).
About signals which are input/output externally when accessing external devices, refer to “Chapter 12.
CONNECTION WITH EXTERNAL DEVICES.”
(1) When fetching instructions into the instruction queue buffer
(2) When reading or writing data to and from the memory•I/O device
operation
= “1.”
For instructions that are affected by the data length flag (m) and the index register length flag (x),
at a time with the timing of waveform (a).
However, when accessing an external device which is connected with the 8-bit external data bus
width (BYTE = “H”), only 1 byte is fetched.
byte with the timing of waveform (a). The contents at the even address are not taken.
bits of data are accessed at a time.
bits of data are accessed separately in 2 operations, 8 bits at a time. Invalid data is not fetched
into the data buffer.
address is not fetched into the data buffer.
address is not fetched into the data buffer.
When the instruction which is next fetched is located at an even address, the BIU fetches 2 bytes
When the instruction which is next fetched is located at an odd address, the BIU fetches only 1
When accessing a 16-bit data which begins at an even address, waveform (a) is applied. The 16
When accessing a 16-bit data which begins at an odd address, waveform (b) is applied. The 16
When accessing an 8-bit data at an even address, waveform (a) is applied. The data at the odd
When accessing an 8-bit data at an odd address, waveform (a) is applied. The data at the even
or
is applied when flag m or x = “0”; operation
7702/7703 Group User’s Manual
or
is applied when flag m or x