h8s-2158 Renesas Electronics Corporation., h8s-2158 Datasheet - Page 226

• Manufacturer Part Number: h8s-2158
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 8 RAM-FIFO Unit (RFU)
Legend:
X: Don't care
Table 8.1 shows how to make settings for BAR, RAR, WAR, and TMP.
In BAR, the bits upper than the boundary become valid depending on the number of FIFO bytes
set in the BUD2 to BUD0 bits. Since the lower bits become invalid, 0 should be written to these
bits. In RAR, WAR, and TMP, the bits lower than the boundary become valid. Since the upper bits
become invalid, 0 should be written to these bits.
Table 8.1
Rev. 3.00 Jan 25, 2006 page 174 of 872
REJ09B0286-0300
Bit
2
1
0
Number of
FIFO Bytes
32 bytes
64 bytes
128 bytes
256 bytes
512 bytes
1024 bytes
2048 bytes
Bit Name
BUD2
BUD1
BUD0
Valid Bits in BAR, RAR, WAR, and TMP
BAR Valid
Section
A19 to A5
A19 to A6
A19 to A7
A19 to A8
A19 to A9
A19 to A10
A19 to A11
Initial Value
1
1
0
BAR Invalid
Section
(Should be
set to 0)
A4
A5 and A4
A6 to A4
A7 to A4
A8 to A4
A9 to A4
A10 to A4
R/W
R/W
R/W
R/W
Description
Boundary 2 to 0
These bits select the FIFO size and the
existence of boundary overflow.
000: 32 bytes
001: 64 bytes
010: 128 bytes
011: 256 bytes
100: 512 bytes
101: 1024 bytes
110: 2048 bytes
111: Boundary is not set
Invalid Sections
in RAR, WAR, and TMP
(Should be set to 0,
no carry)
A10 to A5
A10 to A6
A10 to A7
A10 to A8
A10 and A9
A10
—
Valid Sections
in RAR, WAR,
and TMP
A4 to A0
A5 to A0
A6 to A0
A7 to A0
A8 to A0
A9 to A0
A10 to A0