TC1796
Peripheral Units (Vol. 2 of 2)
Micro Link Interface (MLI)
User’s Manual 23-11 V2.0, 2007-07
MLI, V2.0
23.1.2.1 General Frame Layout
The general layout of a frame is shown in Figure 23-8. It contains the following parts:
• A frame starts with a 4-bit header field that contains a 2-bit frame code (FC) and a 2-
bit pipe number (PN).
• The data field can contain address, data, or control information. The width of the data
field depends on the frame type.
• The frame is terminated by a parity bit (P) with even parity (see Page 23-24),
calculated over header and data field bits.
Figure 23-8 General Frame Layout
The frame code (FC) determines the frame type of the transmitted frame. The pipe
number (PN) indicates the pipe that is related to the frame content (the value of PN is
defined as 00
B
for pipe 0, 01
B
for pipe 1, 10
B
for pipe 2, and 11
B
for pipe 3).
The FC parameter is coded according to Table 23-1. If more than one frame type is
defined with the same frame code value (see FC = 01
H
, 10
H
or 11
H
), the width of the
received frame defines the type. The value given by m in the table below represents the
number of address bits transferred as offset (defined by the buffer size BSx of the
Remote Window x).
Table 23-1 Frame Code Definition
Frame Code
FC
Frame Type Data Field Width [bit] Description
see
00
B
Copy Base Address Frame 32 Page 23-12
01
B
Write Offset and Data Frame 8+m, 16+m, or 32+m Page 23-13
Discrete Read Frame 2+m Page 23-15
10
B
Command Frame 4 Page 23-17
Answer Frame 8, 16, or 32 Page 23-18
11
B
Optimized Write Frame 8, 16, or 32 Page 23-14
Optimized Read Frame 2 Page 23-16
MCA05878
FC = Frame Code
PN = Pipe Number
P = Parity
FC
PN
P
Header Data Field