Flash!

1
Flash!
2
CPU Rewrite

• CPU-rewrite is a term that refers to an Renesas
  MCUs ability to erase/program its own internal
  Flash in circuit.
• R8C is BYTE programmable, where current M16C and
  M32C devices are WORD programmable.
• Old M16C/M32C devices were 256byte programmable.
• In order to erase any data, the ENTIRE block must
  be erase.

3
EW0 vs. EW1 Mode

• HNDc Flash devices can perform Flash operations
  using either EW0 or EW1 Mode.
• EW0 Mode CPU-rewrite Code must be executed out
  of RAM and the Flash register polled for
  operation completion.
• EW1 Mode CPU-rewrite Code is run out of Flash
  (just not in the same block as target block) and
  the CPU is kept in HOLD state until operation
  completion.

4
Block LOCK bit

• Hardware mechanism to protect Flash blocks from
  accidentally be erased/programmed.
• Only on older DINOR, HNDa,b Flash devices
  (M16C/62P,/6N, M32C/83,/85)
• Once a block is locked, it remains that way (even
  through resets) until it is erased.
• To erase a locked block requires and extra step
  in software which disables ALL lock bit settings.
• There are 2 Flash erase commands for this type of
  Flash
• Erase Block (can be used to override lock bit
  settings)
• Erase All unlocked blocks. (can never erase a
  locked block)

5
Block PROTECT bits

• Hardware mechanism to protect Flash blocks from
  accidentally be erased/programmed.
• Will be used for all new devices (R8C, M16C,
  M32C)
• Typically, there are only 2 bits (4 settings) for
  all the Flash Blocks in the device. Therefore,
  blocks are grouped (ie, Block 01, All other user
  blocks)
• Data Flash is never protected.
• Since the protect bits are SET every time you
  enter CPU-rewrite mode, an extra software step is
  required to remove protection to certain blocks.
• The Protect bits reside in the Flash registers.

6
ROM Code Protect

• Disables Flash memory from being read out by a
  parallel programmer.
• The ROMCP register always resides in the last
  byte of Flash (0xFFFFF or 0xFFFFFF)
• Once set, user can only access flash via serial
  boot mode (which has a 7-byte ID code protection
  next page)

7
ROM Code Protect
ROM Code Protect Register
ROMCP
Taken from the M16C/26 Hardware Manual!
8
.
9
Flash Suspend

• Flash writes are fast, erases are slow. The
  bigger the Flash block, the longer the operation
  will take.
• Some newer devices have an Erase Suspend option
  that will allow you to postpone an erase
  operation and leave CPU-rewrite mode before it
  has completed (for example in order to service an
  interrupt). You can then go back into CPU-rewrite
  mode later and continue the erase.

• The HNDe Flash type improves the flash suspend
  response time (from 8ms to 90us). The first
  device to have HNDe will be R8C/20 Series.

10
R8C Flash

• R8C/12 -17 has a Watchdog register at address
  0xFFFF. If that address programmed to 00 (by
  default of NC30 compiler startup file), then the
  watchdog will start firing automatically after
  reset and interfere with CPU-rewrite operations
  that dont account for this.
• The FlashAPI source code does not pet the
  watchdog. Therefore, you must set address FFFF to
  FF in your R8C startup file.

11
Flash Lookup Table
MCU TYPE Write Data Flash Lock/Protect Suspend Notes
R8C/10,11,14,16 HNDc BYTE - Protect Yes W-Dog INTR
R8C/12,13 HNDc BYTE A,B (2k each) Protect Yes W-Dog INTR
R8C/15,17 HNDc BYTE A,B (1k each) Protect Yes W-Dog INTR
M16C/26 HNDc WORD A,B (2k each) Protect Yes only 1 protect bit
M16C/26A,28,29 HNDc WORD A,B (2k each) Protect Yes
M16C/62P,6N HNDc WORD A,1 (4k each) Lock -
M32C/83 DINOR 256 BYTE - Lock - EW0 only
M32C/85,/87 HNDc WORD A,1 (4k each) Lock -

• EW0 and EW1 Mode
• 7 Byte Serial ID code

• ROM Code Protection
• FoUSB Programming

ALL
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Simple Flash API

• R8C, M16C and M32C MCUs with HNDc type Flash are
  similar enough to create one API source file for
  all of them.
• Current supported devices are listed to the
  right.

R8C M16C M32C
R8C/10 M16C/1N2 M32C/83
R8C/11 M16C/26 M32C/84
R8C/12 M16C/26A M32C/85
R8C/13 M16C/28
R8C/14 M16C/29
R8C/15 M16C/62P
R8C/16 M16C/6N4
R8C/17 M16C/6N5
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Flash API Files

• There are only 2 files for the API
• Flash_API.c
• Flash_API.h
• There is a very simple sample program that works
  with all the supported MCU
• FlashAPI_Sample.c
• There is an appnote for using this API
• REU05B0058-2_Simple_Flash_API.pdf
• A Hew project using these files comes with the
  SKPs.

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Flash API Functions

• There are only 2 functions in the API

unsigned char FlashErase( unsigned char block
) unsigned char FlashWrite( FLASH_PTR_TYPE
flash_addr,
BUF_PTR_TYPE buffer_addr,
unsigned int bytes)

• The acceptable values for block in FlashErase
  are listed in FlashAPI.h (BLOCK_0, BLOCK_1, etc)
• The types FLASH_PTR_TYPE and BUF_PTR_TYPE in
  FlashWrite are memory pointers. The have to be
  defined this way in order to deal with the
  different memory models between the R8C, M16C and
  M32C.

success FlashErase( BLOCK_A ) Success
FlashWrite((FLASH_PTR_TYPE)0xF000,
(BUF_PTR_TYPE) hello,
6)
15
Flash API Setup

• You must define the MCU you are using. The list
  of valid devices are at the top of the file
  Flash_API.h.
• define M16C_62P 1
• define R8C_13 0
• You must define the Flash Mode you want to use.
  Mode 0 sends flash command while running from
  RAM. Mode 1 sends command while running in Flash.
  
• define EW_MODE 0
• define EW_MODE 1
• You must define the Bus Clock Frequncy (BCLK) you
  are running at. This is used to determine how
  much to slow the MCU down when sending commands
  to the flash controller.
• define BCLK_FREQUENCY 20000000

16
Flash API Setup

• You can also set up the defines within HEW.

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Flash API Setup

• There are 3 things that must be defined before
  using API. They are all listed in the file
  Flash_API.h.
• If something is not defined, the
• compiler will stop and print out
• a message.

C\FlashAPI\Flash_API.h 179 Error "You must
specify your device in Flash_API.h
first!!" C\FlashAPI\Flash_API.c Phase M16C C
Compiler finished
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New Virtual EEPROM APIs

• The Virtual EEPROM software was created to
• Fix design bugs in the initial release
• Use the new Flash API code
• Account for writing into a Flash space that
  wasnt blank.
• Improve reliability in loss of power situations
• Allow for multiple and uniquely sized data to be
  stored

19
Virtual EEPROM
The Renesas Virtual EEPROM solution is a
software implementation utilizing the two high
Erase-Write cycle Flash blocks.

• The concept is not to erase a flash block every
  time stored data needs to be changed. Instead,
  write the new data to another un-programmed
  location within that flash block until the entire
  block has been filled.
• Reducing the number of erase cycles of a block
  better utilizes and extends the life of the Flash.

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Virtual EEPROM

• The virtual EEPROM API uses the Flash API in
  order to erase/program the Data Flash areas of
  the MCU

User Code
Virtual EEPROM API
Flash API
Data Flash
Data Flash
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Virtual EEPROM

• All new R8C, M16C and M32C MCUs come with two
  Flash blocks with 10,000 erase/write cycle.
• 10,000 E/W versions have special Option codes
  (D7,D9)

M16C/62P BLOCKS A 1 4KB each
M16C/Tiny Series (2x) BLOCKS A B 2KB each
R8C 12,13 BLOCKS A B 2KB each
R8C 15,17 BLOCKS A B 1KB each
M32C/85 BLOCKS A 1 4KB each
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Virtual EEPROM (Fixed Method)

• The user has a single fixed amount of data that
  can be stored referred to a a SEGMENT.
• All the bytes in the SEGMENT must be modified at
  the same time.

Virtual EEPROM
5 WORD array
SEGMENT SIZE 5
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Virtual EEPROM (Fixed Method)

• To change one or more bytes, user application
  must read the SEGMENT array into a RAM buffer,
  modify, then write back.

Virtual EEPROM
Buffer in RAM
VirEE Read
1133 2345 8800 0000 0000
5 WORD array
VirEE Write
1133 2369 8800 0000 0000
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Virtual EEPROM (Multiple/Variable Method)

• The user may have multiple records (segments) of
  variable length that may be modified individually.

Virtual EEPROM
User assigned record label (0-254)
7
24
data
data
1
10
254
17
data
Size in WORDs -1 (1-255)
data
5
50
User data for that record
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Virtual EEPROM Example
include virtEE_Variable.h typedef struct
unsigned char record_label / 0x00 to 0xFE /
unsigned char data_size / number of WORDS
- 1/ unsigned int NV_FAR pData / pointer
to data / NV_type void main(void)
NV_type EE_data / Read Record 1 /
EE_data.record_label 1 NV_Read( EE_data
) value EE_data.pData0 / Write
Record 5 / EE_data.record_label 5
EE_data.pData0 55 EE_data.pData1 22
EE_data.data_size 2 NV_Write( EE_data
)
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Continue in Lab 5