Multi-buffer RAM
1606
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
Multi-Buffered Serial Peripheral Interface Module (MibSPI) with Parallel Pin
Option (MibSPIP)
NOTE:
Refer to the specific device datasheet for the actual number of transmit and receive buffers.
Write to unimplemented buffer is overwriting the corresponding implemented buffer. In
MIBSPI, if the RAM SIZE specified is 32 buffers, write to 33rd buffer overwrites 1st buffer,
write to 34th buffer overwrites 2nd buffer, and so on.
28.4.1 Multi-buffer RAM Auto Initialization
When the MIBSPI is out of reset mode, auto initialization of multi-buffer RAM starts. The application code
must check for BUFINITACTIVE bit to be 0 (multi-buffer RAM initialization is complete) before configuring
multi-buffer RAM.
Besides the default auto initialization after reset, the auto-initialization sequence can also be done by:
1. Enable the global hardware memory initialization key by programming a value of 1010b to the bits [3:0]
of the MINITGCR register of the System module.
2. Set the control bit for the multi-buffer RAM in the MSINENA System module register. This bit is device-
specific for each memory that support auto-initialization. Please refer to the device datasheet to identify
the control bit for the multi-buffer RAM. This starts the initialization process. The BUFINITACTIVE bit
will get set to reflect that the initialization is ongoing.
3. When the memory initialization is completed, the corresponding status bit in the MINISTAT register will
be set. Also, the BUFINITACTIVE bit will get cleared.
4. Disable the global hardware memory initialization key by programming a value of 0101 to the bits [3:0]
of the MINITGCR register of the System module.
Please refer to the Architecture User Guide for more details on the memory auto-initialization process.
NOTE:
During Auto Initialization process, all the multi-buffer mode registers (except MIBSPIE) will
be reset to their default values. So, it should be ensured that Auto Initialization is completed
before configuring the multi-buffer mode register.
28.4.2 Multi-buffer RAM Register Summary
This section describes the multi-buffer RAM control and transmit-data fields of each word of TXRAM, and
the status and receive-data fields of each word of RXRAM. The base address for multi-buffer RAM is
FF0E 0000h for MibSPI1 RAM, FF08 0000h for MibSPI2 RAM, FF0C 000h for MibSPI3 RAM, FF06 0000h
for MibSPI4 RAM, and FF0A 0000h for MibSPI5 RAM.
Table 28-61. Multi-buffer RAM Register
Offset
Acronym
Register Description
Section
Base + 0h-1FFh
TXRAM
Multi-buffer RAM Transmit Data Register
Base + 200h-3FFh
RXRAM
Multi-buffer RAM Receive Buffer Register