Rainbow Electronics W90N740 - Manual (Page 32)

W90N740
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7.2.5.2 Rotate Priority Mode
In Rotate Priority Mode (PRTMOD = 1), the IPEN and IPACT bits have no function (i.e. ignore).
W90N740 used a round robin arbitration scheme ensures that all bus masters (except the External Bus
Master, it always has the first priority) have equal chance to gain the bus and that a retracted master
does not lock up the bus.
7.2.6 Power-On Setting
After power on reset, there are four Power-On setting pins to configure W90N740 system configuration.
Power-On Setting Pin
Internal System Clock Select D15
Little/Big Endian Mode Select D14
Boot ROM/FLASH Data Bus Width D [13:12]
D15 pin：Internal System Clock Select
If pin D15 is pull-down, the external clock from EXTAL pin is served as internal system clock.
If pin D15 is pull-up, the PLL output clock is used as internal system clock.
D14 pin：Little/Big Endian Mode Select
If pin D14 is pull-down, the external memory format is Big Endian mode.
If pin D14 is pull-up, the external memory format is Little Endian mode.
D [13:12] ： Boot ROM/FLASH Data Bus Width
D [13:12] Bus Width
Pull-down Pull-down 8-bit
Pull-down Pull-up 16-bit
Pull-up Pull-down 32-bit
Pull-up Pull-up RESERVED
Note: Related Power-On Setting Pin
D [11:10] ：
D [15] D [11:10] Description
Pull-up Pull High W90N740 normal operation
D [9:8] ：
D [9:8]
Pull-up Pull-up