SH7263 Datasheet, PDF (1046/1862 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7260 Series

Section 20 IEBus^TM Controller (IEB)
20.1.1 IEBus Communications Protocol
An overview of the IEBus is provided below.
• Communications method: Half-duplex asynchronous communications
• Multi-master system
All units connected to the IEBus can transfer data to other units.
• Broadcast communications function (one-to-many communications)
⎯ Group broadcast communications: Broadcast communications to group unit
⎯ General broadcast communications: Broadcast communications to all units
• Mode is selectable (three modes with different transfer speeds)
Table 20.1 Mode Types
IEBφ*¹ = 12, 18, 24, 30, IEBφ*¹ = 12.58, 18.87, 25.16, Maximum Number Of
Mode 36*² MHz
31.45, 37.74*² MHz
Transfer Bytes (byte/frame)
0
About 3.9 kbps
About 4.1 kbps
16
1
About 17 kbps
About 18 kbps
32
2
About 26 kbps
About 27 kbps
128
Notes: 1. Peripheral clock (Pφ), or clocks for AUDIO_X1 and AUDIO_X2
2. Oscillation frequency when this LSI is used
• Access control: CSMA/CD (Carrier Sense Multiple Access with Collision Detection)
Priority of bus mastership is as follows.
⎯ Broadcast communications (one-to-many communications) have priority over normal
communications (one-to-one communications).
⎯ A smaller master address has priority.
• Communications scale
⎯ Number of units: Up to 50
⎯ Cable length: Up to 150 m (when using a twisted-pair cable)
Note: The communications scale of the actual system depends on the characteristics of the
externally mounted IEBus driver/receiver and the cable used.
Rev. 2.00 Mar. 14, 2008 Page 1012 of 1824
REJ09B0290-0200