M37702E6BFS Renesas Electronics America, M37702E6BFS Datasheet - Page 276

• 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

CONNECTION WITH EXTERNAL DEVICES
12.1 Signals required for accessing external devices
12–8
12.1.2 Operation of bus interface unit (BIU)
Figures 12.1.5 and 12.1.6 show the examples of operating waveforms of the signals input and output to
/from externals when accessing external devices. The following explains these waveforms compared with
the basic operating waveform (refer to section “2.2.3 Operation of bus interface unit (BIU).”)
(1) When fetching instructions into instruction queue buffer
(2) When reading or writing data to and from memory•I/O device
data bus width, the BIU first fetches 1 byte in waveform (d), and after that, fetches each two bytes
at a time in waveform (a).
operation
= “1.”
When a branch to an odd address is caused by a branch instruction and others in the 16-bit external
For instructions that are affected by the data length flag (m) and the index register length flag (x),
The setup of flags m and x and the selection of the external data bus width do not affect each other.
bus width, the BIU fetches 2 bytes at a time with the waveform (a). When in the 8-bit external data
bus width, the BIU fetches only 1 byte with the first half of waveform (e).
bus width, the BIU fetches only 1 byte with the waveform (d). When in the 8-bit external data bus
width, the BIU fetches only 1 byte with the first half of waveform (f).
When the instruction which is next fetched is located at an even address in the 16-bit external data
When the instruction which is next fetched is located at an odd address in the 16-bit external data
When accessing 16-bit data which begins at an even address, waveform (a) or (e) is applied.
When accessing 16-bit data which begins at an odd address, waveform (b) or (f) is applied.
When accessing 8-bit data at an even address, waveform (c) or the first half of (e) is applied.
When accessing 8-bit data at an odd address, waveform (d) or the first half of (f) is applied.
or
is applied when flag m or x = “0”; operation
7702/7703 Group User’s Manual
or
is applied when flag m or x