Table of Contents
Advertisement
(12)IEBus communication count register (CCR)
The IEBus communication count register (CCR) indicates the number of remaining bytes in the
communication byte number specified in the communication mode.
Bits 7 to 0 of the IEBus communication count register (CCR) indicate the number of transfer bytes.
This register reads the count value of the counter that is preset to the maximum number of transmitted bytes
(32 bytes) per frame specified in mode 1.
decremented during normal communication (ACK), CCR is decremented when 1 byte has been
communicated, regardless of whether ACK or NACK. When the count value has reached "00H", the frame
end flag (ENDFRAM) is set.
The maximum number of transfer bytes of the preset value of mode 1 per frame is 20H (32 bytes).
After reset: 20H
CCR
(13)IEBus clock selection register (IECLK)
This register selects the clock of IEBus. The main clock frequencies that can be used are shown below.
Main clock frequencies other than the following cannot be used.
• 6.0 MHz/6.291 MHz
• 12.0 MHz/12.582 MHz
More IEBus clock types can be selected for the µ PD703036H, 703036HY, 70F3036H,
Remark
70F3036HY, 703037H, 703037HY, 70F3037H, and 70F3037HY by setting in combination with the
IEBus high-speed clock selection register (IEHCLK).
After reset: 00H
IECLK
582
CHAPTER 19
IEBus CONTROLLER (V850/SB2)
R
Address: FFFFF3F6H
7
6
5
R/W
Address: FFFFF3F8H
7
6
5
0
0
0
IECS
0
@ f
= 6.0 MHz or f
XX
1
@ f
= 12.0 MHz or f
XX
User's Manual U13850EJ6V0UD
Whereas SCR (IEBus communication success counter) is
4
3
2
4
3
2
0
0
0
IEBus clock selection
= 6.291 MHz
XX
= 12.582 MHz
XX
1
0
1
0
0
IECS
Advertisement
Table of Contents
