COBHAM GR712RC User Manual

GR712RC-UM, Jun 2017, Version 2.9 175 www.cobham.com/gaisler
GR712RC
Error Enable (PERRE) bit in the Mask register is set this event will cause an interrupt. The incoming
word may have been a response to an ongoing SEQUENCE operation or to a MASTER-WORD-
SEND READ transfer. Software should abort any ongoing SEQUENCE operation and possibly stop
waiting for the response to a READ operation when the core reports a parity error.
24.2.6 Clock and SYNC generation
To avoid multiple clock domains in the design the core generates the SCLK clock by dividing the sys-
tem clock. The clock divisor is selected by the fields CLKSCALEH and CLKSCALEL in the Clock
Scaler register. The SCLK frequency is calculated with the formula:
The CLKSCALEH determines the number of system clock cycles, plus one, that the SCLK clock is
kept HIGH and the CLKSCALEL value determines how many clock cycles, plus one, that the SCLK
clock is kept low. This scaling constrains the system clock frequency. To generate a 6 MHz, SCLK the
system clock frequency must be a multiple of 6 MHz. To attain a 6 MHz SCLK with 50/50 duty cycle,
the multiple must be dividable by two. The lowest possible system frequency that can be used to gen-
erate a 6 MHz clock is 12 MHz, with both scaler register fields set to zero:
The next frequency that will generate a SCLK clock with a 6 MHz period is a system clock of 18
MHz. This system frequency does not allow a SCLK clock with a 50/50 duty cycle.
24.3 Registers
The core is programmed through registers at address. 0x80000800
Table 185.GRSLINK registers
APB address offset Register
0x08000080 Clock Scaler register
0x80000804 Control register
0x80000808 NULL word register
0x8000080C Status register
0x80000810 IRQ mask register
0x80000814 Array A base address register
0x80000818 Array B base address register
0x8000081C Transmit register
0x80000820 Receive register
Table 186. GRSLINK Clock Scaler register
31 21 20 16 15 5 4 0
RESERVED CLKSCALEH RESERVED CLKSCALEL
31:21 RESERVED
SCLK
SystemClockFrequency
CLKSCALEH 1+CLKSCALEL 1++
---------------------------------------------------------------------------------------------------------------
=
SCLK
SystemClockFrequency
CLKSCALEH 1+CLKSCALEL 1++
---------------------------------------------------------------------------------------------------------------
12MHz
01+01++
---------------------------------------------
12MHz
2
------------------
6MHz====

COBHAM GR712RC Specifications

General

Brand	COBHAM
Model	GR712RC
Category	Computer Hardware
Language	English