Signal

Direction

Description

VME_DS1_N

Input

VME Data Strobe 1: Active low signal used for the selected location part of the data.

VME_WRITE_N

Input

VME Read/Write: Active low signal which is used by the master to indicate the data direction.

VME_BERR_N

Input

VME Bus Error: Active low signal driven by other modules indicating that the data transfer was unsuccessful.

VME_IACK_N

Input

VME Interrupt Acknowledge: When driven low, the VME_IACKIN_N causes the IACK daisy-chain driver,

located in slot 1, to propagate a falling edge down the interrupt acknowledge daisy-chain.

VME_IACKIN_N

Input

VME Interrupt Acknowledge Input Daisy-Chain: This active low signal is used as input of the module for the

daisy-chain interrupt acknowledge.

VME_IACKOUT_N

Output

VME Interrupt Acknowledge Output Daisy-Chain: This active low signal is used as output of the module for

the daisy-chain interrupt acknowledge.

VME_IRQ_N[6:0]

Output

VME Interrupt Request Lines: Interrupters request interrupts by driving an interrupt request line low.

VME_IRQ_N[7] has the highest priority. These signals have to be connected to open collector drivers.

INT_USER_ADDR[31:1]

Output

Registered VME Address Bus: Synchronized on the falling edge of VME_AS_N. This bus is used to decode

the address and to active an access signal on the user part.

INT_USER_AM[5:0]

Output

Registered VME Address Modifier Bus: Synchronized on the falling edge of VME_AS_N. This bus is used

to decode the address modifier and to active an access signal on the user part.

USER_ACCESS

Input

User Access Signal: The user has 50 ns time to decode the address and asserting the USER_ACCESS

signal when addressed.

USER_ACC_REQ

Output

User Access Request: Active high signal which requests for an access on the VME bus. Valid until USER_

ACC_RDY acknowledges the request (or VME bus error occurs).

USER_ACC_RDY

Input

User Side Acknowledgement Signal: Acknowledge the request of the access on the VME bus of the user

part.

USER_ADDR[31:1]

Output

User Address: Address used for the access on the user part.

USER_AM[5:0]

Output

User Address Modifier: Address modifier used for the access on the user part.

USER_WR_DATA[31:0]

Output

User Write Data: The data[31:24] are valid while USER_BE4 is high, data[23:16] while USER_BE3,

data[15:8] while USER_BE2 and data[7:0] while USER_BE1.

USER_RD_DATA[31:0]

Input

User Read Data: The read data has to be valid when USER_ACC_RDY is high.

USER_RW_N

Output

User Read/Write Signal: A low signal indicates that the data are written in the user part and a low signal, that

the data are read.

USER_BE1

Output

User Byte 1 Enable: Active high signal enabling the low byte [7:0] of the data.

USER_BE2

Output

User Byte 2 Enable: Active high signal enabling the high byte [15:8] of the data.

USER_BE3

Output

User Byte 3 Enable: Active high signal enabling the high byte [23:16] of the data.

USER_BE4

Output

User Byte 4 Enable: Active high signal enabling the high byte [31:24] of the data.

USER_IREQ

Input

User Interrupt request: This active high signal indicates that an interrupt is pending on a VME interrupt will

be generated. It will return to zero with USER_IACK active.

USER_IACK

Output

User Interrupt Acknowledge: An active one event which indicates the end of a valid interrupt acknowledge

cycle.

USER_ILEV[2:0]

Input

User Interrupt Level: This bus indicates the level of priority of the pending interrupt. It will generate the

corresponding VME_IRQ.

USER_IVEC[31:0]

Input

User Interrupt Vector: The interrupt vector will be transmitted on the VME data bus during the

acknowledgement of the interrupt.

Table 2: VME Core Signal List