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Hi all,
- For our project we are modifying the reference design of MPPT solar charger (http://www.cypress.com/?rID=39126)
- Our plan is to include a UART module to serially transmitt the parameters monitored to an external data logger.
- The available resources in the current design is not enough to include a UART module, so we have to modify it
- Two digital block are needed for UART module in the current design one digital block is free
Following are the design modification we have in mind.....
1.In the design there are four LEDs used for displaying the current status of the battery. we thought of disabling the LEDs which would free two more digital blocks (which are used as PWM for driving those LEDs) and take out the LEDS from the board and connect some wires in its and use those pins for serial outputs.(which we feel a bit awkward)
2. There are two pins ISSP_SCK_1_1(connected to P1_0) and ISSP_SDATA_1_0(P1_1), we thought of using these pins for the RXD and TXD. Can this pin be multiplexed as ISSP while programming and as RXD and TXD while execution?? is that possible?.. This seems quite decent since we can use the available MOLEX pin out in the board which is used for programming
3.Another option would be to use the pins used for OCD(on chip debugging) for pins are used. Is it possible to route the signals from the UART block to these pins??
We are uncertain about the feasibilty of the modifications 2 & 3. So we are kindly expecting your suggestions.
Any sort of help would be greatly appreciated.
Thanks,
Sundar
Solved! Go to Solution.
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If you look at following ap note you will see specific conditions about dual role
of pins to observe in terms of loading, and also confirmation that what you are
trtying to do, dual use of ISSP pins in other functions, is OK.
http://www.cypress.com/?docID=35792
This page more general -
http://www.cypress.com/?rID=2908
Regards, Dana.
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Take a look at this, there are programming ISSP specs and an ap note on programming.
Basically give you the functionality of the pions, how the device uses pins as dual function
pins.
http://www.cypress.com/?rID=2906
Essentially you can connect UART to these pins, they are GPIO and can be used as such.
Regards, Dana.
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One other comment, on receive side, where you have a RS232 translator
driving the programming input pin, SDA, use a wired OR or jumper to
get RS232 translator off the pin during programming. Wired or can be
something as trivial as diode gate or single gate logic, if you are con-
cerned about nosie margin. They are cheap, small packages.
Regards, Dana.
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Hi Dana,
I looked into the links you provided. I can't afford an HSSP in my design.
In the current design(http://www.cypress.com/?rID=39126) the P1_0 and P1_1 pins are routed to SDATA and SCLK of ISSP resply. So by modifying this ,if i route these pins to global busses and inturn to Rx and Tx of UART.Will i not be able to program my PSoC next time? since those pins are not routed to SDA and SCLK anymore?...
And if this is the case is there a possibilty of Dynamic routing ...like initially after reset the Psocs P1_0 and P1_1 pins are routed to ISSP and during execution it can be dynamically re routed to the Rx and Tx of UART?
Since i am a beginner, i am struggling a bit with this.
Kindly help me.
Thanks
Sundar
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The ISSP comes together with a protocol that is part of the PSoC1 OS. OS?? Yes, there are a handfull of rudimental functions pre-programmed (not erasable) into the chip and the programming algorithms via ISSP is one of them.
At initial power-up or reset sequence the system finds out whether a programmer is connected through ISSP and acts accordingly. Since your UART is not yet initialzed and its ports not yet routed, there is no conflict on the I/O-lines, so you do not have to care for that.
Bob
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If you look at following ap note you will see specific conditions about dual role
of pins to observe in terms of loading, and also confirmation that what you are
trtying to do, dual use of ISSP pins in other functions, is OK.
http://www.cypress.com/?docID=35792
This page more general -
http://www.cypress.com/?rID=2908
Regards, Dana.
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Shall anyone to support for getting MMPT & SOLAR CHARGER ALGORITHM FOR PSOC 5LP.
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