Datasheet

LPC Interface Bridge Registers (D31:F0)
Intel® Xeon® Processor D-1500 Product Family 273
Datasheet - Volume 1 of 4: Integrated Platform Controller Hub
March 2015
7.4.10 ELCR1—Master Controller Edge/Level Triggered Register
Offset Address: 4D0h Attribute: R/W
Default Value: 00h Size: 8 bits
In edge mode, (bit[x] = 0), the interrupt is recognized by a low to high transition. In
level mode (bit[x] = 1), the interrupt is recognized by a high level. The cascade
channel, IRQ2, the heart beat timer (IRQ0), and the keyboard controller (IRQ1),
cannot be put into level mode.
7.4.11 ELCR2—Slave Controller Edge/Level Triggered Register
Offset Address: 4D1h Attribute: R/W
Default Value: 00h Size: 8 bits
In edge mode, (bit[x] = 0), the interrupt is recognized by a low to high transition. In
level mode (bit[x] = 1), the interrupt is recognized by a high level. The real time clock,
IRQ8#, and the floating point error interrupt, IRQ13, cannot be programmed for level
mode.
1:0 Register Read Command — WO. These bits provide control for reading the In-Service Register
(ISR) and the Interrupt Request Register (IRR). When bit 1=0, bit 0 will not affect the register read
selection. When bit 1=1, bit 0 selects the register status returned following an OCW3 read. If bit
0=0, the IRR will be read. If bit 0=1, the ISR will be read. Following ICW initialization, the default
OCW3 port address read will be “read IRR”. To retain the current selection (read ISR or read IRR),
always write a 0 to bit 1 when programming this register. The selected register can be read
repeatedly without reprogramming OCW3. To select a new status register, OCW3 must be
reprogrammed prior to attempting the read.
00 = No Action
01 = No Action
10 = Read IRQ Register
11 = Read IS Register
Bit Description
Bit Description
7 IRQ7 ECL — R/W.
0 = Edge
1 = Level
6 IRQ6 ECL — R/W.
0 = Edge
1 = Level
5 IRQ5 ECL — R/W.
0 = Edge
1 = Level
4 IRQ4 ECL — R/W.
0 = Edge
1 = Level
3 IRQ3 ECL — R/W.
0 = Edge
1 = Level
2:0 Reserved. Must be 0.
Bit Description
7 IRQ15 ECL — R/W.
0 = Edge
1 = Level