3.0 Definitions
TABLE 1. Signal Descriptions for the LSC
Pin Symbol | Pin Name | I/O | Description |
UD[31..0] | User Data input lines | Input to S-LINK | Data on these lines is transferred to the LSC on a low-to-high transition of UCLK when UWEN is low. UD[3..0] are ignored if UCTRL# is low. Synchronous with UCLK. |
LFF# | Link Full Flag | Output from S-LINK | Data shall only be written to the S-LINK when this line is high. After it goes low, up to two more words may be written. Functional when S-LINK is in test mode. Undefined when URESET# is low. Synchronous with UCLK. |
URESET# | User Reset line | Input to S-LINK | When low initiates a reset cycle. Asynchronous. |
UTEST# | User Test line | Input to S-LINK | When low switches the LSC to test mode. Causes LDOWN# to go low. Asynchronous. |
UDW[1..0] | User Data Width lines | Input to S-LINK | Define the data width the S-LINK is to be operated in. Data width codes at LSC and LDC must be the same. Sampled after a reset cycle. |
UCTRL# | User Control line | Input to S-LINK | When low indicates that the data to be transmitted is a control word. Causes UD[3..0] to be ignored. Synchronous with UCLK. |
UWEN# | User Write Enable | Input to S-LINK | When low enables data to be transferred to the S-LINK on the low-to-high transition of UCLK. Synchronous with UCLK. |
UCLK | User Clock | Input to S-LINK | Data is transferred to the S-LINK on the low-to-high transitions of UCLK when UWEN# is low. This is a free running clock. |
LRL[3..0] | Link Return Lines | Output from S-LINK | These lines reflect the state of URL[3..0] at the LDC. In the simplex version these lines are not functional. A simplex FEMB shall leave these lines unconnected. A simplex LSC shall connect these lines to GND. Asynchronous, even relative to each other. |
LDOWN# | Link Down | Output from S-LINK | When low indicates that the S-LINK is not operational. Asynchronous. Can go low due to: - S-LINK failure; then LDOWN# is latched low until cleared by a reset cycle. - S-LINK undergoing reset cycle, then LDOWN# goes high when reset cycle is complete. - S-LINK in test mode, then LDOWN# goes high when test mode is ended. The FEMB shall pull LDOWN# low if the LSC is not present or not powered up. |
TABLE 2. Signal Descriptions for the LDC
Pin Symbol | Pin Name | I/O | Description |
LD[31..0] | Link Data output lines | Output from S-LINK | Data present on these lines may be latched on the low-to-high transition of LCLK when LWEN# is low. LD[3..0] have special meanings when LCTRL# is low. Synchronous with LCLK. |
UXOFF# | User Transmit Off | Input to S-LINK | When low, signals the LSC to stop transmitting data. Functions in test mode if UTDO# is low but does not stop transmission of test pattern if UTDO# is high. Asynchronous. In the simplex version this pin is not functional. A simplex ROMB shall pull-up this line to Vcc. A simplex LDC shall leave this line unconnected. |
URESET# | User Reset line | Input to S-LINK | When low initiates a reset cycle. Asynchronous. |
UTDO# | User Test Data Out | Input to S-LINK | When low, the received test pattern is transferred from the LDC to the ROMB during test mode. Sampled after a reset cycle. |
UDW[1..0] | User Data Width lines | Input to S-LINK | Define the data width the S-LINK is to be operated in. Data width codes at LSC and LDC must be the same. Sampled after a reset cycle. |
LCTRL# | Link Control line | Output from S-LINK | When low indicates that a control word is being transferred. Causes LD[3..0] to have a special meaning. Synchronous with LCLK. |
LWEN# | Link Write Enable line | Output from S-LINK | When low indicates that valid data will be transferred to the ROMB on the low-to-high transition of LCLK. Synchronous to LCLK. |
LCLK | Link Clock | Output from S-LINK | Data is transferred to the ROMB on each low-to-high transition of LCLK when LWEN# is low. This is a free-running clock if LDOWN# is high. If LDOWN# is low, this signal is undefined. |
LDERR# | Link Data Error | Output from S-LINK | When low indicates that a data transmission error has occurred or that a pattern error has occurred during test mode. With word-by-word error reporting, LDERR# goes low with the word in error and with the control word for that block. With block basis error reporting, LDERR# goes low only with the control word for the block containing the word with error. |
URL[3..0] | User Return Lines | Input to S-LINK | The state of these lines is sampled, transmitted back to the LSC and presented on LRL[3..0]. Asynchronous, even relative to each other. In the simplex version these pins are not functional. A simplex ROMB shall connect these lines to GND. A simplex LDC shall leave these lines unconnected. |
LDOWN# | Link Down | Output from S-LINK | When low indicates that the S-LINK is not operational. Asynchronous. Can go low due to: - S-LINK failure; then LDOWN# is latched low until cleared by a reset cycle. - S-LINK undergoing reset cycle, then LDOWN# goes high when reset cycle is complete. - S-LINK in test mode, then LDOWN# goes high when test mode is ended. The ROMB shall pull LDOWN# low if the LDC is not present or not powered up. |