HD64F3337YCP16V Datasheet, PDF (476/749 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Table 20.7 On-Board Programming Mode Selection
Mode Selections
Boot mode
Mode 2
FV _PP
12 V*
MD₁
12 V*
MD₀
0
Mode 3
12 V*
1
User programming
mode
Mode 2
Mode 3
1
0
1
1
Notes
0: V_IL
1: V_IH
Note: * For details on the timing of 12 V application, see notes 6 to 8 in the Notes on Use of Boot
Mode at the end of this section.
In boot mode, the mode control register (MDCR) can be used to monitor the mode (mode 2
or 3) in the same way as in normal mode.
Example: Set the mode pins for mode 2 boot mode (MD₁ = 12 V, MD₀ = 0 V).
If the mode select bits of MDCR are now read, they will indicate mode 2 (MDS1 = 1,
MDS0 = 0).
20.3.1 Boot Mode
To use boot mode, a user program for programming and erasing the flash memory must be
provided in advance on the host machine (which may be a personal computer). Serial
communication interface channel 1 is used in asynchronous mode. If the H8/3337YF is placed in
boot mode, after it comes out of reset, a built-in boot program is activated. This program starts by
measuring the low period of data transmitted from the host and setting the bit rate register (BRR)
accordingly. The H8/3337YF’s built-in serial communication interface (SCI) can then be used to
download the user program from the host machine. The user program is stored in on-chip RAM.
After the program has been stored, execution branches to address H'F7E0 in the on-chip RAM,
and the program stored on RAM is executed to program and erase the flash memory. Figure 20.4
shows the boot-mode execution procedure.
HOST
Receive data to be programmed
Transmit verification data
H8/3337YF
RxD₁
SCI
TxD₁
Figure 20.3 Boot-Mode System Configuration
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