SBS Technologies IndustryPack PCI-60A, User Manual

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9
Status and Control Register Bit Maps
Three registers reside within the PCI-60A Local Control space as shown in Figures 2 and
3. The relative offsets and bit map definitions follow:
CNTL0: BAR2 offset 0x00000500 = Control Register 0 [CNTL0]
D15 D14 D13 D12 D11 D10 D9 D8
Unused Unused Unused Unused Unused Unused CLKF CLKE
D7 D6 D5 D4 D3 D2 D1 D0
INTSET INTEN AUTO_ACK CLR_AUTO CLKD CLKC CLKB CLKA
Bit Definition
CLKA 0 = 8 MHz, 1 = 32 MHz for IP slot A
CLKB 0 = 8 MHz, 1 = 32 MHz for IP slot B
CLKC 0 = 8 MHz, 1 = 32 MHz for IP slot C
CLKD 0 = 8 MHz, 1 = 32 MHz for IP slot D
CLR_AUTO 0 = clear, 1 = enable AUTO_INT_SET bit in CNTL2
AUTO_ACK 0 = disable, 1 = enable bus error timer
INTEN 0 = disable interrupts, 1 = enable interrupts
INTSET 0 = turn off, 1 = force local interrupt [INTEN = 1]
CLKE 0 = 8 MHz, 1 = 32 MHz for IP slot E
CLKF 0 = 8 MHz, 1 = 32 MHz for IP slot F
Default value = 0x00. Word access and read-writeable.
CLK[A..F]
The CLKx bits control the clock rate for each IndustryPack. The clock to the slot is always
at the frequency selected. The State Machine clock is altered to match the slot clock rate
for each access automatically. A PLL is used to allow clean switching between
frequencies without “glitching”. For the 8 MHz only version, these bits have no affect.
CLR_AUTO
The CLR_AUTO control bit is used to enable and clear the AUTO_INT_SET bit in
CNTL2. The AUTO_INT_SET bit is held clear when this bit is “0”. Setting this bit to “1”
removes the clear from the AUTO_INT_SET bit, allowing it to be set when the bus error
timer expires and an Ack* is generated for an IndustryPack. Once the AUTO_INT_SET
bit is set, a “0” must be written to the CLR_AUTO bit to clear the AUTO_INT_SET bit.
The CLR_AUTO bit must be set back to “1” to re-enable the AUTO_INT_SET bit. The
CLR_AUTO bit defaults to “0” on power-up or after a reset.
AUTO_ACK
The AUTO_ACK bit enables the auto acknowledge feature when set to “1”. When
enabled, the PCI-60A creates a response to the PCI bus if an IndustryPack does not
respond within 3.2 µsec or is not present. A response will be generated for valid
IndustryPack addresses only. Clearing this bit to “0” will disable this function. If the
CLR_AUTO, AUTO_ACK, and INTEN are all set to “1”, an interrupt will be generated if
the software accesses a location that does not respond. The software must read CNTL2
and, if necessary, CNTL1 to determine the source of the interrupt. AUTO_ACK can be
used with INTEN disabled and CLR_AUTO enabled by polling the status after each
access. The power-up and reset default is “0”.
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