Rainbow Electronics DS3131 - Manual (Page 20)

DS3131
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3.2 Serial Port Interface Signal Description
Signal Name:
RC0 to RC39
Signal Description:
Receive Serial Clock
Signal Type: Input
Data can be clocked into the device either on rising edges (normal clock mode) or falling edges (inverted clock
mode) of RC. This is programmable on a per port basis. RC can operate at speeds from DC to 52MHz. Clock
gapping is acceptable. If not used, this signal should be wired low.
Signal Name:
RD0 to RD39
Signal Description: Receive Serial Data
Signal Type: Input
Can be sampled either on the rising edge of RC (normal clock mode) or the falling edge of RC (inverted clock
mode). If not used, this signal should be wired low.
Signal Name:
TC0 to TC39
Signal Description:
Transmit Serial Clock
Signal Type: Input
Data is clocked out of the device at TD either on rising edges (normal clock mode) or falling edges (inverted clock
mode) of TC. This is programmable on a per port basis. TC can operate at speeds from DC to 52MHz. Clock
gapping is acceptable. If not used, this signal should be wired low.
Signal Name:
TD0 to TD39
Signal Description:
Transmit Serial Data
Signal Type:
Output
Can be updated either on the rising edge of TC (normal clock mode) or the falling edge of TC (inverted clock
mode). TD can be forced either high or low by the TP[n]CR register. See Section
6.1 for details.
3.3 Local Bus Signal Description
Note:
The signals listed in this section are only active when the local bus is enabled.
Signal Name: LMS
Signal Description:
Local Bus Mode Select
Signal Type:
Input
This signal should be connected low when the device operates with no local bus access or if the local bus is used
as a bridge from the PCI bus. This signal should be connected high if the local bus is to be used by an external host
to configure the device.
0 = local bus is in the PCI bridge mode (master)
1 = local bus is in the configuration mode (slave)
Signal Name:
LIM
Signal Description:
Local Bus Intel/Motorola Bus Select
Signal Type: Input
The signal determines whether the local bus operates in the Intel mode (LIM = 0) or the Motorola mode (LIM =
1). The signal names in parenthesis are operational when the device is in the Motorola mode.
0 = local bus is in the Intel mode
1 = local bus is in the Motorola mode