examples/am335x/PRU_ADC_onChip: bug fixesv5.4.0

Fixed several bugs in PRU_ADC_onChip:

	* pru_adc_userspace.c
		- changed firmware name from PRU_ADC.out to PRU_ADC_onChip.out
		- changed size of RPMsg read from MAX_BUFFER_SIZE to
			RPMSG_MESSAGE_SIZE

	* pru_adc_firmware.c
		- reduced noise in single-ended ADC voltage measurements by
			setting SEL_INM_SWC_3_0=0x8 (VREFN) for each STEPCONFIG
			register

	* README.txt
		- changed PRU_ADC to PRU_ADC_onChip

Signed-off-by: Nick Saulnier <nsaulnier@ti.com>

3 files changed, 13 insertions, 5 deletions

diff --git a/examples/am335x/PRU_ADC_onChip/README.txt b/examples/am335x/PRU_ADC_onChip/README.txt
index 55693e8..047598b 100644
--- a/examples/am335x/PRU_ADC_onChip/README.txt
+++ b/examples/am335x/PRU_ADC_onChip/README.txt
@@ -46,7 +46,7 @@ PRU_ADC
        |--pru_adc_userspace.c userspace code that interacts with PRU0
 
 BUILD FIRMWARE & USERSPACE CODE
-$ cd <PATH_TO_PRU_SW_SUPPORT_PACKAGE>/examples/am335x/PRU_ADC/
+$ cd <PATH_TO_PRU_SW_SUPPORT_PACKAGE>/examples/am335x/PRU_ADC_onChip/
 $ make clean
 $ make
 $ cd pru_adc_userspace/
@@ -55,9 +55,9 @@ $ make
 
 LOAD FIRMWARE & USERSPACE CODE ONTO BOARD
 PRU firmware and ARM userspace code are generated in the gen/ folders of
-PRU_ADC/ and PRU_ADC/pru_adc_userspace/ respectively.
+PRU_ADC_onChip/ and PRU_ADC_onChip/pru_adc_userspace/ respectively.
 
-Load the PRU firmware PRU_ADC.out onto the BeagleBone Black at
+Load the PRU firmware PRU_ADC_onChip.out onto the BeagleBone Black at
 /lib/firmware/
 
 Load the ARM userspace code pru_adc_userspace onto the BeagleBone Black at
diff --git a/examples/am335x/PRU_ADC_onChip/pru_adc_firmware.c b/examples/am335x/PRU_ADC_onChip/pru_adc_firmware.c
index 8744005..7abe5eb 100644
--- a/examples/am335x/PRU_ADC_onChip/pru_adc_firmware.c
+++ b/examples/am335x/PRU_ADC_onChip/pru_adc_firmware.c
@@ -175,11 +175,13 @@ void init_adc()
          * Mode = 0; SW enabled, one-shot
          * Averaging = 0x3; 8 sample average
          * SEL_INP_SWC_3_0 = 0x4 = Channel 5
+         * SEL_INM_SWC_3_0 = 1xxx = VREFN (reduces noise in single ended mode)
          * use FIFO0
          */
         ADC_TSC.STEPCONFIG1_bit.MODE = 0;
         ADC_TSC.STEPCONFIG1_bit.AVERAGING = 3;
         ADC_TSC.STEPCONFIG1_bit.SEL_INP_SWC_3_0 = 4;
+        ADC_TSC.STEPCONFIG1_bit.SEL_INM_SWC_3_0 = 8;
         ADC_TSC.STEPCONFIG1_bit.FIFO_SELECT = 0;
 
         /*
@@ -187,11 +189,13 @@ void init_adc()
          * Mode = 0; SW enabled, one-shot
          * Averaging = 0x3; 8 sample average
          * SEL_INP_SWC_3_0 = 0x5 = Channel 6
+         * SEL_INM_SWC_3_0 = 1xxx = VREFN (reduces noise in single ended mode)
          * use FIFO0
          */
         ADC_TSC.STEPCONFIG2_bit.MODE = 0;
         ADC_TSC.STEPCONFIG2_bit.AVERAGING = 3;
         ADC_TSC.STEPCONFIG2_bit.SEL_INP_SWC_3_0 = 5;
+        ADC_TSC.STEPCONFIG2_bit.SEL_INM_SWC_3_0 = 8;
         ADC_TSC.STEPCONFIG2_bit.FIFO_SELECT = 0;
 
         /* 
@@ -199,11 +203,13 @@ void init_adc()
          * Mode = 0; SW enabled, one-shot
          * Averaging = 0x3; 8 sample average
          * SEL_INP_SWC_3_0 = 0x6 = Channel 7
+         * SEL_INM_SWC_3_0 = 1xxx = VREFN (reduces noise in single ended mode)
          * use FIFO0
          */
         ADC_TSC.STEPCONFIG3_bit.MODE = 0;
         ADC_TSC.STEPCONFIG3_bit.AVERAGING = 3;
         ADC_TSC.STEPCONFIG3_bit.SEL_INP_SWC_3_0 = 6;
+        ADC_TSC.STEPCONFIG3_bit.SEL_INM_SWC_3_0 = 8;
         ADC_TSC.STEPCONFIG3_bit.FIFO_SELECT = 0;
 
         /* 
@@ -211,11 +217,13 @@ void init_adc()
          * Mode = 0; SW enabled, one-shot
          * Averaging = 0x3; 8 sample average
          * SEL_INP_SWC_3_0 = 0x7= Channel 8
+         * SEL_INM_SWC_3_0 = 1xxx = VREFN (reduces noise in single ended mode)
          * use FIFO0
          */
         ADC_TSC.STEPCONFIG4_bit.MODE = 0;
         ADC_TSC.STEPCONFIG4_bit.AVERAGING = 3;
         ADC_TSC.STEPCONFIG4_bit.SEL_INP_SWC_3_0 = 7;
+        ADC_TSC.STEPCONFIG4_bit.SEL_INM_SWC_3_0 = 8;
         ADC_TSC.STEPCONFIG4_bit.FIFO_SELECT = 0;
 
         /* 
diff --git a/examples/am335x/PRU_ADC_onChip/pru_adc_userspace/pru_adc_userspace.c b/examples/am335x/PRU_ADC_onChip/pru_adc_userspace/pru_adc_userspace.c
index 6abdef0..12f2d28 100644
--- a/examples/am335x/PRU_ADC_onChip/pru_adc_userspace/pru_adc_userspace.c
+++ b/examples/am335x/PRU_ADC_onChip/pru_adc_userspace/pru_adc_userspace.c
@@ -122,7 +122,7 @@ static uint16_t readADCchannel(const char *adcChannel)
 
                 FILE *sysfs_node;
                 char firmware[] = "/sys/class/remoteproc/remoteproc1/firmware";
-                char firmwareName[] = "PRU_ADC.out";
+                char firmwareName[] = "PRU_ADC_onChip.out";
                 sysfs_node = fopen(firmware, "r+");
                 if (sysfs_node == NULL) {
                         printf("cannot open firmware sysfs_node");
@@ -194,7 +194,7 @@ static uint16_t readADCchannel(const char *adcChannel)
         }
 
         /* read voltage and channel back */
-        size_t freadResult = read(pfds[0].fd, payload, MAX_BUFFER_SIZE);
+        size_t freadResult = read(pfds[0].fd, payload, RPMSG_MESSAGE_SIZE);
         returnedVoltage = ((shared_struct *)payload)->voltage;
 
         close(pfds[0].fd);