MC908QB8CDWE Freescale Semiconductor, MC908QB8CDWE Datasheet - Page 206

IC MCU 8BIT 8K FLASH 16-SOIC

MC908QB8CDWE

Manufacturer Part Number
MC908QB8CDWE
Description
IC MCU 8BIT 8K FLASH 16-SOIC
Manufacturer
Freescale Semiconductor
Series
HC08r
Datasheet

Specifications of MC908QB8CDWE

Core Processor
HC08
Core Size
8-Bit
Speed
8MHz
Connectivity
SCI, SPI
Peripherals
LVD, POR, PWM
Number Of I /o
13
Program Memory Size
8KB (8K x 8)
Program Memory Type
FLASH
Ram Size
256 x 8
Voltage - Supply (vcc/vdd)
2.7 V ~ 5.5 V
Data Converters
A/D 10x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
16-SOIC (0.300", 7.5mm Width)
Processor Series
HC08QB
Core
HC08
Data Bus Width
8 bit
Data Ram Size
256 B
Interface Type
SCI, SPI
Maximum Clock Frequency
8 MHz
Number Of Programmable I/os
14
Number Of Timers
4
Operating Supply Voltage
3 V to 5 V
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
Development Tools By Supplier
FSICEBASE, M68CBL05AE, DEMO908QB8, DEMO908QC16
Minimum Operating Temperature
- 40 C
On-chip Adc
10 bit
For Use With
DEMO908QB8 - BOARD DEMO FOR MC68HC908QB8
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Eeprom Size
-
Lead Free Status / Rohs Status
 Details

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Development Support
17.3.2 Security
A security feature discourages unauthorized reading of FLASH locations while in monitor mode. The host
can bypass the security feature at monitor mode entry by sending eight security bytes that match the
bytes at locations $FFF6–$FFFD. Locations $FFF6–$FFFD contain user-defined data.
During monitor mode entry, the MCU waits after the power-on reset for the host to send the eight security
bytes on pin PTA0. If the received bytes match those at locations $FFF6–$FFFD, the host bypasses the
security feature and can read all FLASH locations and execute code from FLASH. Security remains
bypassed until a power-on reset occurs. If the reset was not a power-on reset, security remains bypassed
and security code entry is not required. See
Upon power-on reset, if the received bytes of the security code do not match the data at locations
$FFF6–$FFFD, the host fails to bypass the security feature. The MCU remains in monitor mode, but
reading a FLASH location returns an invalid value and trying to execute code from FLASH causes an
illegal address reset. After receiving the eight security bytes from the host, the MCU transmits a break
character, signifying that it is ready to receive a command.
To determine whether the security code entered is correct, check to see if bit 6 of RAM address $80 is
set. If it is, then the correct security code has been entered and FLASH can be accessed.
If the security sequence fails, the device should be reset by a power-on reset and brought up in monitor
mode to attempt another entry. After failing the security sequence, the FLASH module can also be mass
erased by executing an erase routine that was downloaded into internal RAM. The mass erase operation
clears the security code locations so that all eight security bytes become $FF (blank).
206
Notes:
1 = Echo delay, approximately 2 bit times
2 = Data return delay, approximately 2 bit times
3 = Wait 1 bit time before sending next byte
4 = Wait until clock is stable and monitor runs
Do not leave locations $FFF6–$FFFD blank. For security reasons, program
locations $FFF6–$FFFD even if they are not used for vectors.
The MCU does not transmit a break character until after the host sends the
eight security bytes.
V
RST
PA0
DD
Figure 17-18. Monitor Mode Entry Timing
FROM HOST
4096 + 32 BUSCLKX4 CYCLES
FROM MCU
MC68HC908QB8 Data Sheet, Rev. 3
4
Figure
NOTE
NOTE
1
17-18.
3
1
1
2
Freescale Semiconductor
3
1

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