ST92F120V1Q7 STMicroelectronics, ST92F120V1Q7 Datasheet - Page 33

• Manufacturer Part Number: ST92F120V1Q7
• Description: Microcontrollers (MCU) Flash 128K SPI/I2C
• Manufacturer: STMicroelectronics

Specifications of ST92F120V1Q7

• Data Bus Width: 8 bit, 16 bit
• Program Memory Type: Flash
• Program Memory Size: 128 KB
• Data Ram Size: 4 KB
• Interface Type: I2C, SPI
• Maximum Clock Frequency: 24 MHz
• Number Of Programmable I/os: 77
• Number Of Timers: 5
• Maximum Operating Temperature: + 105 C
• Mounting Style: SMD/SMT
• Package / Case: PQFP-100
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit, 16 Channel
• Lead Free Status / Rohs Status: No

2.6 ADDRESS SPACE EXTENSION
To manage 4 Mbytes of addressing space, it is
necessary to have 22 address bits. The MMU
adds 6 bits to the usual 16-bit address, thus trans-
lating a 16-bit virtual address into a 22-bit physical
address. There are 2 different ways to do this de-
pending on the memory involved and on the oper-
ation being performed.
2.6.1 Addressing 16-Kbyte Pages
This extension mode is implicitly used to address
Data memory space if no DMA is being performed.
The Data memory space is divided into 4 pages of
16 Kbytes. Each one of the four 8-bit registers
(DPR[3:0], Data Page Registers) selects a differ-
ent 16-Kbyte page. The DPR registers allow ac-
cess to the entire memory space which contains
256 pages of 16 Kbytes.
Data paging is performed by extending the 14 LSB
of the 16-bit address with the contents of a DPR
register. The two MSBs of the 16-bit address are
interpreted as the identification number of the DPR
register to be used. Therefore, the DPR registers
Figure 18. Addressing via DPR[3:0]
DPR0
00
DPR1
01
MMU registers
8 bits
22-bit physical address
DPR2
10
DPR3
11
are involved in the following virtual address rang-
es:
The contents of the selected DPR register specify
one of the 256 possible data memory pages. This
8-bit data page number, in addition to the remain-
ing 14-bit page offset address forms the physical
22-bit address (see
A DPR register cannot be modified via an address-
ing mode that uses the same DPR register. For in-
stance, the instruction “POPW DPR0” is legal only
if the stack is kept either in the register file or in a
memory location above 8000h, where DPR2 and
DPR3 are used. Otherwise, since DPR0 and
DPR1 are modified by the instruction, unpredicta-
ble behaviour could result.
14 LSB
ST92F120 - DEVICE ARCHITECTURE
DPR0: from 0000h to 3FFFh;
DPR1: from 4000h to 7FFFh;
DPR2: from 8000h to BFFFh;
DPR3: from C000h to FFFFh.
16-bit virtual address
Figure
10).
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