R5F21257SNFP#U0 Renesas Electronics America, R5F21257SNFP#U0 Datasheet - Page 91

• Manufacturer Part Number: R5F21257SNFP#U0
• Description: IC R8C/25 MCU FLASH 52LQFP
• Manufacturer: Renesas Electronics America
• Series: R8C/2x/25r

Specifications of R5F21257SNFP#U0

• Core Processor: R8C
• Core Size: 16/32-Bit
• Speed: 20MHz
• Connectivity: I²C, LIN, SIO, SSU, UART/USART
• Peripherals: POR, Voltage Detect, WDT
• Number Of I /o: 41
• Program Memory Size: 48KB (48K x 8)
• Program Memory Type: FLASH
• Ram Size: 2.5K x 8
• Voltage - Supply (vcc/vdd): 2.2 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 52-LQFP
• For Use With: R0K521256S000BE - KIT EVAL STARTER FOR R8C/25
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

R8C/24 Group, R8C/25 Group
Rev.3.00
REJ09B0244-0300
9.
The bus cycles differ when accessing ROM/RAM, and when accessing SFR.
Table 9.1 lists Bus Cycles by Access Space of the R8C/24 Group and Table 9.2 lists Bus Cycles by Access Space of
the R8C/25 Group.
ROM/RAM and SFR are connected to the CPU by an 8-bit bus. When accessing in word (16-bit) units, these areas are
accessed twice in 8-bit units.
Table 9.3 lists Access Units and Bus Operations.
However, only following SFRs are connected with the 16-bit bus:
Timer RD: registers TRDi (i = 0,1), TRDGRAi, TRDGRBi, TRDGRCi, and TRDGRDi
Therefore, they are accessed once in 16-bit units. The bus operation is the same as “Area: SFR, data flash, even address
byte access” in Table 9.3 Access Units and Bus Operations, and 16-bit data is accessed at a time.
Table 9.1
Table 9.2
Table 9.3
SFR
ROM/RAM
SFR/Data flash
Program ROM/RAM
Bus
Even address
Even address
Word access
Word access
Odd address
Byte access
Odd address
Byte access
Access Area
Access Area
Area
Feb 29, 2008
Bus Cycles by Access Space of the R8C/24 Group
Bus Cycles by Access Space of the R8C/25 Group
Access Units and Bus Operations
CPU clock
CPU clock
CPU clock
CPU clock
Address
Address
Address
Address
Data
Data
Data
Data
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2 cycles of CPU clock
1 cycle of CPU clock
2 cycles of CPU clock
1 cycle of CPU clock
SFR, data flash
Odd
Even
Bus Cycle
Bus Cycle
Data
Data
Even
Odd
Even+1
Odd+1
Data
Data
Data
Data
CPU clock
CPU clock
CPU clock
CPU clock
Address
Address
Address
Address
Data
Data
Data
Data
ROM (program ROM), RAM
Odd
Even
Odd
Even
Data
Data
Data
Data
Even+1
Odd+1
Data
Data
9. Bus