| Line 5... |
Line 5... |
DIY calculator address space:
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DIY calculator address space:
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$F038 : Tx data register (write)
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$F038 : Tx data register (write)
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$F018 : Rx data register (read)
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$F018 : Rx data register (read)
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$F039 : command register (write)
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$F039 : command register (write)
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$F019 : status register (read)
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$F019 : status register (read)
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$F03A : address mid register (write)
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$F03A : address low register (write)
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$F03B : address low register (write)
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$F03B : address mid register (write)
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$F03B : address high register (write)
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The high address byte is fixed to $0F, denoting the last segment within
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The high address byte is fixed to $0F, denoting the last segment within
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the flash (8MBit type assumed).
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the flash (8MBit type assumed).
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These are the bits of the status register:
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These are the bits of the status register:
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busy: $01
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busy: $01
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tx empty: $02
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tx empty: $02
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rx ready: $04
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rx ready: $04
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wait for data: $08
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Other bits read as '0'.
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Other bits read as '0'.
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How to communicate with the SPI flash:
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How to communicate with the SPI flash:
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--------------------------------------
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--------------------------------------
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| Line 104... |
Line 106... |
JZ [WAIT]
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JZ [WAIT]
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; read the response
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; read the response
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LDA [SPI_RX]
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LDA [SPI_RX]
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3) issue the "Sector Erase" command:
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3) issue the "Sector Erase" command:
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LDA 0
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; symbolic constant
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SECTOR .EQU $0F ; sector number
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.
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.
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.
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LDA SECTOR
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STA [SPI_AHI]
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STA [SPI_AHI]
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LDA 0
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STA [SPI_AMID]
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STA [SPI_ALO]
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STA [SPI_ALO]
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LDA SPI_SE
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LDA SPI_SE
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STA [SPI_CMD]
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STA [SPI_CMD]
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4) issue the "Read Data" command:
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4) issue the "Read Data" command:
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| Line 128... |
Line 137... |
.
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.
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; code:
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; code:
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BLDX BUFSIZE
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BLDX BUFSIZE
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BSTX [MAXBYTES]
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BSTX [MAXBYTES]
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LDA BUF
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LDA SECTOR
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STA [SPI_AHI]
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STA [SPI_AHI]
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LDA BUF
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STA [SPI_AMID]
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LDA BUF+1
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LDA BUF+1
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STA [SPI_ALO]
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STA [SPI_ALO]
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LDA SPI_RD
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LDA SPI_RD
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STA [SPI_CMD]
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STA [SPI_CMD]
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BLDX 0
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BLDX 0
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| Line 163... |
Line 174... |
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Remarks:
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Remarks:
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--------
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--------
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The flash utilizes a 3 byte address (using 20 bits for the 8Mbit
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The flash utilizes a 3 byte address (using 20 bits for the 8Mbit
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M25P80 chip). The highest byte specifies the sector on which the PP, SE,
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M25P80 chip). The highest byte specifies the sector on which the PP, SE,
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RD, F_RD commands operate. Currently we use only the topmost sector
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RD, F_RD commands operate. In the DIY Calculator we use only the topmost
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(no. 0x0F). This is no restriction in size of memory since one sector
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sector (no. 0x0F).
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is 64KB in size. But it saves the additional high byte address register.
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The high byte (0x0F) is hardwired inside the SPI Flash controller.
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The PP, RD, and F_RD commands are special in that that the number of bytes
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The PP, RD, and F_RD commands are special in that that the number of bytes
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to be transferred is not known in advance. Therefore the dummy "NOP" command
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to be transferred is not known in advance. Therefore the dummy "NOP" command
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must be issued to the SPI Flash controller after all bytes are transferred
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must be issued to the SPI Flash controller after all bytes are transferred
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to terminate the active command and return the SPI Flash controller to its
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to terminate the active command and return the SPI Flash controller to its
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