Hi Wassim,

     Thanks for the reply! I've actually tried using 5D or BA>>1 as the address, but to no avail - the sensor still could not acknowledge the slave address. I now am thinking about skipping the register addressing part since I have a demo board and a development software. These two, when used, are capable of loading sensor register default values. Thus, instead of using the TWI to load sensor register values, I plan to use the demo board along with its software. Do you think that would be okay? Oh and by the way, can you be so kind as to guide me on how I could check the contents of the SDRAM? The program that I have places the pixel data from the sensor into the SDRAM. I really have no idea as to how I could check its content. I know I'm asking too much, but I really would appreciate it if you could help me.

Regards,

     Allan

Hi Wassim,

    Thanks for the help! I really appreciate it. I've actually tried the 0x90>>1 address. However, it still did not work. I tried using a logic analyzer to check the SCL of the TWI. Apparently, the SCL only had high transitions. Hence, leaving me with the conclusion that the SCL is the problem. With the SCL not working properly, data transfer would also not work properly. I think that this is the the reason as to why the sensor did not acknowledge the slave address.

     The program that I have is the sample program for interfacing the Blackfin 537 to the MT9V022 sensor, which is found in the VDSP 4.5 folder. I've modified the program in such a way that it would work for the MT9V135 sensor, considering sensor datasheet and Blackfin manuals. Now my questions are: (1) What could be the possible reasons as to why the SCL did not seem to work properly?; and (2) Would the BF537 settings (system clock settings, core clock settings, TWI clock prescale settings, clock division settings and duty cycles) be entirely different for the MT9V135 sensor as compared to the MT9V022 sensor? Again, any help will do and will be greatly appreciated.

Regards,    

     Allan

Hi Wassim,

     There has been a mistake. Apparently, there is a working SCL. I've also checked the PLL settings. The VCO of the system is set at 0x3000 or 600MHz with a clock in of 25MHz. System clock is set at 120MHz (VCO/5) and core clock is 600MHz (VCO/1). Prescale is 12 (120MHz/10MHz). TWI_DIV hi and low are 50 each considering a duty cycle of 50%. Below are screenshots of the TWI register values considering 0xBA and 0x90 addresses.

     As you can see, the problem still persists - the sensor still does not acknowledge the slave address designated by the TWI. Thus, I still can't write the default sensor register values into their respective registers. Does it have something to do with the TWI slave register not set? Because according to the hardware reference manual, specifically, the programming model of the master mode, one has to 'WRITE TO TWI_SLAVE_CTL TO ENABLE SLAVE FUNCTIONALITY'. Do I really need to do this? Apparently, I've read a contrasting statement that says slave mode does not affect master mode operation. Thus, I really am confused.

     However, I've still modified the program considering the programming model and enabling the slave register. What happened was the master mode operation did happen. However, instead of a master transmit happening, a master receive event occured. Still, no sensor register write had occurred.

     I know I've troubled you enough, Wassim; and for all your help, I thank you. However, if you could at least somehow tell me the other possible reasons as to why the problem still persists, then I would appreciate it. I badly need your help since I really can't tell where the problem comes from.

Regards,

     Allan

Hi Wassim,

     I've checked the sensor schematic. The sensor has pull-up resistors that are 10k Ohms each. Actually, the sensor works fine when interfaced with a micron demo board. In addition, when it is interfaced to the AV-Extender of the BF board and its output is tapped and projected onto an LCD, there are no problems at all. The sensor works fine and is able to diplay images at 30fps. Therefore, I think that there are no problems at all with the sensor.

     Now, could it be possible that the problem is with the program code? I really and honestly think that there is something missing with the program code. I've attached the program code here. If you have time, then please take a look at it. Wassim, thank you very much for your patience and for all your help. I really am grateful to you.

Regards,

     Allan

Hi guys,

     Great news! The sensor is now working fine. We've already captured images. However, the problem with the TWI still persists. I still am working on it. Thanks for all your help. I really appreciate it.

Regards,

     Allan