LS1028A cfg_gpinput pin connections

[Sbayley]

Hello,

The design checklist for the LS1028A states that the cfg_gpinput pins have "Default "1111 1111", values can be application defined". What is the purpose of these configuration pins? Do I need to set them or can I rely on the internal pull ups on these pins to put it in the default configuration?

Thank you,

Sean

[Sbayley]

Thank you this is very helpful!

[June_Lu]

Please refer LS1028A Reference Manual page 246, 9.2.1.4 General-Purpose POR Configuration Register (GPPORCR1)

"

GPPORCR stores the value sampled from the SDHC2_DAT[3:0],SDHC1_DAT[3:0] signals using sampling logic similar to that for the configuration pins. It is provided for customer use and always samples 8-bits. Software can use this value to inform the operating system about initial system configuration. Typical interpretations include circuit board type, board ID number, or a list of available peripherals.

"

The default is "1111 1111" if you do not use it.

Please refer to LS1028A/LS1018A Data Sheet , Table 1. Pinout list by bus, Note 4, cfg_gpinputX(X=0-8)

"

4. This pin is a reset configuration pin. It has a weak (~20 kΩ) internal pull-up P-FET that is enabled only when the processor is in its reset state. This pull-up is designed such that it can be overpowered by an external 4.7 kΩ resistor. However, if the signal is intended to be high after reset, and if there is any device on the net that might pull down the value of the net at reset, a pull-up or active driver is needed.

"