SM320VC5510A-EP Datasheet, PDF (25/82 Pages) Texas Instruments – SM320VC5510A-EP Fixed-Point Digital Signal Processor

Functional Overview
3.2.1 System Register (SYSR)
The 5510 system register (SYSR) provides control over certain device-specific functions. SYSR is located at
port address 07FDh.
15
10
9
8
7
Reserved
HPE
BH
HBH
R−000000
R/W−1 R/W−0 R/W−0
LEGEND: R = Read, W = Write, n = value after reset
6
BOOTM3
R−0
5
Reserved
R−0
4
Reserved
R/W−0
3
Reserved
R/W−0
Figure 3−3. System Register (SYSR) Bit Layout
2
0
CLKDIV
R/W−000
BIT
NO.
15−10
BIT
NAME
Reserved
9
HPE
8
BH
7
HBH
6
BOOTM3
5
Reserved
4
Reserved
3
Reserved
2−0 CLKDIV
RESET
VALUE
000000
1
0
0
0
0
0
0
000
Table 3−5. System Register (SYSR) Bit Functions
FUNCTION
These bits are reserved and are unaffected by writes.
EHPI pullup/pulldown enable. Enables the internal pullups on the EHPI control pins HCS, HAS, HR/W,
HMODE, HCNTL0, and HA1/HCNTL1. Enables the internal pulldowns on EHPI control pins HBE0 and
HBE1.
HPE = 0
Pullups and pulldowns disabled
HPE = 1
Pullups and pulldowns enabled.
EMIF data bus holder enable. Enables internal bus holders on D[31:0].
BH = 0
EMIF data bus holders disabled.
BH = 1
EMIF data bus holders enabled.
EHPI data bus holder enable. Enables internal bus holders on HD[15:0].
HBH = 0
EHPI data bus holders disabled.
HBH = 1
EHPI data bus holders enabled.
BOOTM3 status. This read-only bit represents the state of the BOOTM3 pin.
This bit is reserved and is unaffected by writes.
This bit is reserved and must be written as 0.
This bit is reserved and is unaffected by writes.
CLKOUT divide factor. Allows the clock present on the CLKOUT pin to be a divided-down version of the
internal CPU clock. This field does not affect the programming of the PLL
CLKDIV = 000 CLKOUT represents the CPU clock divided by 1
CLKDIV = 001 CLKOUT represents the CPU clock divided by 2
CLKDIV = 010 CLKOUT represents the CPU clock divided by 4
CLKDIV = 011 CLKOUT represents the CPU clock divided by 6
CLKDIV = 100 CLKOUT represents the CPU clock divided by 8
CLKDIV = 101 CLKOUT represents the CPU clock divided by 10
CLKDIV = 110 CLKOUT represents the CPU clock divided by 12
CLKDIV = 111 CLKOUT represents the CPU clock divided by 14
August 2003 − Revised November 2003
SGUS045A
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