NS9750 - Training Hardware

BBus Utility Block

BBus Utility Overview Contains global BBus functions including: Master Peripheral Resets BBus DMA Interrupts ARM Wake-up USB Configuration Endian-ness Configuration General Purpose I/O (GPIO)

BBus Utility – Master Reset Master Reset Register contains reset control bits for each BBus peripheral block: Bbus Utility, BBus DMA, I2C, IEEE 1284, USB and the Serial Controllers (4) Resets asserted by default after power-on Reset bits must be de-asserted following power-on reset for each BBus peripheral.

BBus Utility – DMA Interrupts DMA Interrupt Status/Enable registers include 1-bit for each of the 16 BBus DMA Channels. Refer to the Users Manual for BBus DMA channel assignments. DMA Interrupt Status Register should be used to determine which DMA Channel is responsible for setting the BBus Bridge DMA Interrupt Pending status bit .

BBus Utility Configuration USB Configuration Register contains Speed and Host/Device mode control bits. Refer to the USB documentation in the Users Manual for further information. Endian-ness Configuration Register controls the Little/Big endian orientation of each of the BBus peripherals and the AHB Master. Endian-ness of the AHB Master must always match that of the AHB Bus.

BBus Utility – ARM Wake-up It is possible to Wake-up a sleeping ARM processor by matching pre-defined byte characters on the Serial Controller ‘A’ receive interface. Should any Rx character byte match a byte in the ARM Wake-Up Register, a wakeup signal will be forwarded from the Bbus to the System Controller Module (SCM).

BBus Utility – GPIOs 50 General Purpose I/O (GPIO) bits Each bit can be programmed to select one of the 4 Functions behind that GPIO pin. For example, GPIO[0] can be allocated to: Function 0: Ser ChanA TxData _OR_ Function 1: AHB DMA Chan0 Done _OR_ Function 2: Timer 1 _OR_ Function 3: generic GPIO bit<0>

BBus Utility – GPIOs Each GPIO Configuration Registers (#1 - #7) control 8 GPIO pins, using 4-bits to select direction and function per GPIO pin. Refer to the NS9750 DataSheet for GPIO Mux function assigments. For general purpose bits, select Function 3 and specify the pin direction.

BBus Utility – GPIOs Use GPIO Control Registers to drive the desired value onto the associated output pin. Use GPIO Status Registers to read the input value from the associated input pin. Refer to the Users Manual for GPIO bit assignments in the Configuration, Control and Status Registers.

Hints & Kinks Do all general purpose I/Os (GPIO) have the same drive strength? No. Most GPIO pins have 2 mA drive strength with the following two exceptions. LCD Clock requires 8 mA drive strengh All other LCD outputs require 4 mA drive strength.