6 emif and usb byte access – Texas Instruments TMS3320C5515 User Manual

Page 75

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System Configuration and Control

Table 1-59. Peripheral Reset Control Register (PRCR) Field Descriptions (continued)

Bit

Field

Value

Description

5

PG3_RST

Peripheral group 3 software reset bit. Drives the MMC/SD0, MMC/SD1, I2S0, and I2S1 reset signal.

Write 0

Writing zero has no effect

Write 1

Writing one starts resetting the peripheral group

Read 0

Reading zero means that peripheral group is out of reset

Read 1

Reading one means the peripheral group is being held in reset and should not be accessed

4

DMA_RST

DMA software reset bit. Drives the reset signal to all four controllers.

Write 0

Writing zero has no effect

Write 1

Writing one starts resetting the peripheral group

Read 0

Reading zero means that peripheral group is out of reset

Read 1

Reading one means the peripheral group is being held in reset and should not be accessed

3

USB_RST

USB software reset bit. Drives the USB reset signal.

Write 0

Writing zero has no effect

Write 1

Writing one starts resetting the peripheral group

Read 0

Reading zero means that peripheral group is out of reset

Read 1

Reading one means the peripheral group is being held in reset and should not be accessed

2

SAR_RST

SAR software reset bit and reset for most analog-related register in the IO-space address range of
0x7000-0x70FF

Write 0

Writing zero has no effect

Write 1

Writing one starts resetting the peripheral group

Read 0

Reading zero means that peripheral group is out of reset

Read 1

Reading one means the peripheral group is being held in reset and should not be accessed

1

PG1_RST

Peripheral group 1 software reset bit. Drives the EMIF and all three timer reset signal.

Write 0

Writing zero has no effect

Write 1

Writing one starts resetting the peripheral group

Read 0

Reading zero means that peripheral group is out of reset

Read 1

Reading one means the peripheral group is being held in reset and should not be accessed

0

I2C_RST

I2C software reset bit. Drives the I2C reset signal.

Write 0

Writing zero has no effect

Write 1

Writing one starts resetting the peripheral group

Read 0

Reading zero means that peripheral group is out of reset

Read 1

Reading one means the peripheral group is being held in reset and should not be accessed

1.7.6 EMIF and USB Byte Access

The C55x CPU architecture cannot generate 8-bit accesses to its data or I/O space. But in some cases
specific to the USB and EMIF peripherals, it is necessary to access a single byte of data. For example,
when writing byte commands to NAND Flash devices.

For these situations, the upper or lower byte of a CPU word access can be masked using the BYTEMODE
bits of the EMIF system control register (ESCR) and the USB system control register (USBSCR). The
BYTEMODE bits of ESCR only affect accesses to the external memory and the EMIF registers. The
BYTEMODE bits of USBSCR only affect CPU accesses to the USB registers.

Table 1-60

and

Table 1-61

summarize the effect of the BYTEMODE bits for different CPU operations.

NOTE:

The BYTEMODE bits of the EMIF system control register should only be used for controlling

CPU accesses to NAND Flash devices and EMIF registers.

75

SPRUFX5A – October 2010 – Revised November 2010

System Control

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