SSC050-01 Datasheet, PDF (66/79 Pages) Maxim Integrated Products – Two-Wire Serial Backplane Controller

Control Registers
Control Register Definition
SSC050-01
Data Sheet
FDh: Backplane Controller Option (BCO)
Register Name:
Address:
Reset Value:
Description
BCO
FDh
X000_XXXXb
Backplane Controller Interrupt Status Register
7
6
5
4
3
2
1
0
Tach Filter
Extend
Pulse Width Modulation
Divider Select
Bit(s) Bit Label
6 TFE
5:4 PDS1-0
Access Description
R/W Tach Filter Extend
Setting this bit causes the input filters on P1.0 through P2.7 to be extended from a
two stage voting circuit to a five stage voting circuit. Additional noise immunity of
approximately 300 nanoseconds will be achieved. This bit enables the filter exten-
sion logic on all tach inputs and is independent of the tach control logic. The
extended filters on P1.0 through P2.7 can be used in other applications with noisy
signaling that require an enhanced input filter. After a reset or power-on, this register
bit will be cleared to a zero, enabling normal input filter operation.
R/W Pulse Width Modulation Divider Select
These two bits determine the divider that is used for the pulse width modulation cir-
cuits. The base frequency range of all pulse width modulation circuits are controlled
by these bits. Each pulse width modulation circuit can be programmed to select one
of the three available frequencies within the range. After a reset or power-on, these
register bits will be cleared to a zero. The following table describes the available fre-
quency ranges:
Table 4-10: Pulse Width Modulation Frequencies
PDS1
0
0
1
1
PDS0
0
1
0
1
Pulse Width Modulation Frequency Range
26KHz, 52KHz or 104KHz (divide by 3)
5.2KHz, 10.4KHz or 20.8KHz (divide by 15)
1.04KHz, 2.08KHz or 4.16KHz (divide by 75)
208Hz, 416Hz, 833Hz (divide by 375)
Revision 4.0
November 10, 2004
4-50