SPNA135A Datasheet, PDF (9/15 Pages) Texas Instruments – Compatibility Considerations: TMS570LS20x/10x to TMS570LS31x/21x

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Package Differences
4.2.2 RAM Trace Port (RTP)
The RTP signals on LS31x/21x microcontrollers are all multiplexed with ETM signals are not available
independently. Therefore, there is no compatibility between the mapping of RTP signals on the 337 BGA
ball-maps of LS31x/21x and LS20x/10x microcontrollers. However, the balls that carry the RTP signals on
LS20x/10x are left as no connects on LS31x/21x. RTP is typically not used when the application is running
and is only used during application debug. Keeping this in mind, this incompatibility only affects the ability
to debug using the RTP on both LS31x/21x and LS20x/10x using a common circuit board.
4.2.3 Local Interconnect Network (LIN)
There are two LIN modules on LS20x/10x while there is only one LIN module on the LS31x/21x
microcontrollers. The balls for the LIN TX and RX signals on LS31x/21x are the same as those for the
LIN2 TX and LIN2 RX signals on LS20x/10x.
Also note that the base address of the LIN module on the LS31x/21x is the same as that of the LIN1
module on the LS20x/10x microcontrollers.
4.2.4 Standard Serial Peripheral Interface 2 (SPI2)
The LS31x/21x include a standard SPI module in addition to the three multi-buffered SPI modules:
MibSPI1, MibSPI3, MibSPI5. The LS20x/10x does not have a standard SPI module, and the
corresponding balls are left unconnected on these microcontrollers.
4.2.5 Analog-to-Digital Converter (ADC)
The LS20x/10x and LS31x/21x microcontrollers both contain two instances of the 12-bit analog-to-digital
converter (ADC) modules. There are 8 analog input channels shared between ADC1 and ADC2 on the
LS20x/10x while there are 16 analog input channels shared between ADC1 and ADC2 on the LS31x/21x
microcontrollers. The additional shared channels are listed below.
• Ball R16, AD2IN[7] is also shared with AD1IN[23]
• Ball R19, AD2IN[6] is also shared with AD1IN[22]
• Ball T15, AD2IN[5] is also shared with AD1IN[21]
• Ball U15, AD2IN[4] is also shared with AD1IN[20]
• Ball U16, AD2IN[3] is also shared with AD1IN[19]
• Ball U14, AD2IN[2] is also shared with AD1IN[18]
• Ball U13, AD2IN[1] is also shared with AD1IN[17]
• Ball V13, AD2IN[0] is also shared with AD1IN[16]
The LS20x/10x microcontrollers also have a dedicated ball, W13, for the AD2EVT signal. This signal is
multiplexed with some other functions on the LS31x/21x microcontrollers and is available on ball V10.
SPNA135A – October 2011
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Compatibility Considerations: TMS570LS20x/10x to TMS570LS31x/21x
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