EVM5509A Plus FAQ
1.1 How do I measure the core DSP current?
The core voltage regulator (U26) generates the 1.6V/1.35V/1.10V core DSP voltage. The output is fed through a 0.1 ohm shunt resistor (R51) to obtain a small voltage proportional to the current passing through the DSP core. This voltage is amplified by a factor of 50 in U47, then further amplified by the op-amp (U40B) for a total gain of 150. The resulting voltage can be seen on pin 7 of U40, or pin 68 of the National Instruments interface connector (P3).
For a typical core current of 150mA, the voltage across the shunt is 0.15V. When this is amplified by a factor of 150, you will see about 2.25V on pin 68 of the National Instruments interface connector.
[Background] The current measuring shunt in intentionally small becauase any voltage lost across the shunt also lowers the DSP voltage. The amplification makes it easier to measure the shunt voltage without special equipment and also helps to drive the signal through the NI cable.
2.1 How do I program the EVM5509A USB?
TI supports the 5509A chip with their Chip Support Library (CSL), located at: http://focus.ti.com/docs/toolsw/folders/print/sprc133.html, which includes built in USB support.
Note: this version of the CSL already comes pre-installed in Code Composer ver. 2.21 and does not need to be downloaded.
Spectrum Digital also offers a USB example demo to send & receive data using the CSL and LibUsb-Win32 usb drivers. For more info on this example look in the Board Support Package for the USB Example.
3.1 Errata for Release 1.00
The current software release has a small bug in the Board Support Library SROM module. It will cause the SROM test to fail on some boards. To fix this issue, download a new copy of evm5509_srom.c here are replace the copy in c:\ti\boards\evm5509a\bsl\evm5509bsl. Rebuild the BSL and any code linked with the BSL and any SROM issues should go away.