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Has anybody implemented NAND flash driver on LPC210x ? Now we are considering using LPC2106 in our project which needs a NAND flash to storage data. Two UARTs, I2C and SPI are all used for other functions. If p0.23 to p0.31 is used for NAND flash data pins, it will occupy the pins for JTAG2, so that we can't use JTAG to debug anymore. Any idea on it ? Shinn |
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Anybody implement NAND flash driver on LPC210x ?
Started by ●April 1, 2004
Reply by ●April 1, 20042004-04-01
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berrycake33 wrote: > > Has anybody implemented NAND flash driver on LPC210x ? > > Now we are considering using LPC2106 in our project which needs > a NAND flash to storage data. > Two UARTs, I2C and SPI are all used for other functions. > If p0.23 to p0.31 is used for NAND flash data pins, it will occupy > the pins for JTAG2, so that we can't use JTAG to debug anymore. Why is the I2C and SPI all used up? Do you really have the entire I2C address space used up? Why can't you spare one of the GPIO lines as an SPI chip select and have an SPI flash? > > Shinn > ABS |
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Reply by ●April 1, 20042004-04-01
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--- In , Alaric B Snell <alaric@a...> wrote: > berrycake33 wrote: > > > > Has anybody implemented NAND flash driver on LPC210x ? > > > > Now we are considering using LPC2106 in our project which needs > > a NAND flash to storage data. > > Two UARTs, I2C and SPI are all used for other functions. > > If p0.23 to p0.31 is used for NAND flash data pins, it will occupy > > the pins for JTAG2, so that we can't use JTAG to debug anymore. > > Why is the I2C and SPI all used up? Do you really have the entire I2C > address space used up? Why can't you spare one of the GPIO lines as an > SPI chip select and have an SPI flash? SPI gives up to about 128kbytes in a single chip. With NAND flash you can get up to 256MBytes in a single chip. Also, NAND write speed is far faster. -- Charles |
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Reply by ●April 2, 20042004-04-02
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On Thursday 01 April 2004 20:37, berrycake33 wrote: > Has anybody implemented NAND flash driver on LPC210x ? > > Now we are considering using LPC2106 in our project which needs > a NAND flash to storage data. > Two UARTs, I2C and SPI are all used for other functions. > If p0.23 to p0.31 is used for NAND flash data pins, it will occupy > the pins for JTAG2, so that we can't use JTAG to debug anymore. > > Any idea on it ? > > Shinn To implemt a NAND interface you will need more than just the 8 data pins, you will also need: CLE, ALE, CE, RE and WE. You can probably ignore the R/B line and jsut read back status. Assuming you are not using SPI at the same time as the NAND, youcould potentially multiplex the SPPI data pins with two NAND pins and save two pins. NAND is pretty fun stuff. I suggest you go read stuff about NAND on the linux mtd and YAFFS www. -- CHarles |
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Reply by ●April 2, 20042004-04-02
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> > Why is the I2C and SPI all used up? Do you really have the
entire > I2C > > address space used up? Why can't you spare one of the GPIO lines as > an > > SPI chip select and have an SPI flash? > > SPI gives up to about 128kbytes in a single chip. With NAND flash you > can get up to 256MBytes in a single chip. On Atmel's DataFlash you get up to like 8 Mbytes in a SPI device, and also with a handy dual RAM cache. The need to write sectors sequentially for levelling is a pain though. |
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Reply by ●April 2, 20042004-04-02
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--- In , Charles Manning <manningc2@a...> wrote: > To implemt a NAND interface you will need more than just the 8 data pins, you > will also need: > > CLE, ALE, CE, RE and WE. > > You can probably ignore the R/B line and jsut read back status. > > Assuming you are not using SPI at the same time as the NAND, youcould > potentially multiplex the SPPI data pins with two NAND pins and save two pins. > > NAND is pretty fun stuff. I suggest you go read stuff about NAND on the linux > mtd and YAFFS www. > > -- CHarles We had considered NAND control pins, they are posited on the rest pins. For easy implementing the NAND flash driver, we'd like to put NAND data pins in a byte alignment. That would save some instructions, although the Philips Set-Clear GPIO operation already costs more instructions to implement data I/O. ( anybody know that why Philips uses this kind of GPIO operation instead of direct setting 0 or 1 ? ) As for I2C and SPI, we use I2C for LCD and SPI for SD Card. Besides, we need to transfer data from NAND to SD Card. |
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Reply by ●April 2, 20042004-04-02
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embeddedjanitor wrote: > SPI gives up to about 128kbytes in a single chip. With NAND flash you > can get up to 256MBytes in a single chip. > > Also, NAND write speed is far faster. Are there really no large NAND flash chips with an SPI interface? I've seen SPI Flash with megabytes on, Atmel do a range of such chips. > -- Charles ABS |
Reply by ●April 2, 20042004-04-02
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At 05:46 AM 4/2/04 +0000, you wrote: >That would save some instructions, although the Philips Set-Clear >GPIO operation already costs more instructions to implement data I/O. >( anybody know that why Philips uses this kind of GPIO operation >instead of direct setting 0 or 1 ? ) The obvious reason for doing this is to avoid conflicts from multiple process (or interrupts). Other wise you have to maintain shadow copies of the outputs and (in an interrupt protected piece of code) update the shadow and then the output. In psuedo code something like: disable_interrupts() shadow_output = shadow_output & ~PERIPH_MASK -- zero area to be updated shadow_output = shadow_output | (new_value & PERIPH_MASK) -- update with new value actual_output = shadow_output; enable_interrupts() Some other micros provide similar facilities. The ST10 uses a construct where a single register affects the I/O bit but maps two bit in the register to each output, one bit patter set the output, a second clears the output and the other two cause no effect. It's also used on internal registers to avoid race conditions on bits that may be affected by both the peripheral HW and SW. Finally note the writeup on the IOPIN register in the user manual "Note: for test purposes, writing to this register stores the value in the output register, bypassing the need to use both the IOSET and IOCLR registers. This feature is of little or no use in an application because it is not possible to write to individual bytes in this register." Robert " 'Freedom' has no meaning of itself. There are always restrictions, be they legal, genetic, or physical. If you don't believe me, try to chew a radio signal. " Kelvin Throop, III |
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Reply by ●April 3, 20042004-04-03
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On Friday 02 April 2004 17:46, berrycake33 wrote: > We had considered NAND control pins, > they are posited on the rest pins. > For easy implementing the NAND flash driver, > we'd like to put NAND data pins in a byte alignment. Byte alignment is not really a big issue. When you read/write the GPIO all this costs extra is an extra shift (which is a cheap operation - free in many cases on ARM). You do however want your pins to be consecutive if possible (ie D0=P0.n... D7=P0.n+7) > That would save some instructions, although the Philips Set-Clear > GPIO operation already costs more instructions to implement data I/O. > ( anybody know that why Philips uses this kind of GPIO operation > instead of direct setting 0 or 1 ? ) This is one of the first things that really seemed stupid the firt time I looked at a micro that had set/clear registers. However it is actually very efficient for cases where a register is used from multiple threads of execution (eg. main loop and an interrupt service routine). With set/clear, you just go ahead and set or clear pins. If you did not have this you'd need to use a shadow register and disable/enable interrupts which gets far more costly. > > As for I2C and SPI, we use I2C for LCD and SPI for SD Card. > Besides, we need to transfer data from NAND to SD Card. OK, I'll bite. Since you have to support SD card anyway, why not just use a second SD card instead of the NAND? -- Charles |
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Reply by ●April 3, 20042004-04-03
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On Friday 02 April 2004 16:03, microbit wrote: > > > Why is the I2C and SPI all used up? Do you really have the entire > > > > I2C > > > > > address space used up? Why can't you spare one of the GPIO lines as > > > > an > > > > > SPI chip select and have an SPI flash? > > > > SPI gives up to about 128kbytes in a single chip. With NAND flash you > > can get up to 256MBytes in a single chip. > > On Atmel's DataFlash you get up to like 8 Mbytes in a SPI device, and also > with a > handy dual RAM cache. > The need to write sectors sequentially for levelling is a pain though. NAND gives you up to 256MBytes in a single chip and is faster. -- CHarles |
