SN32F280 Series
32-Bit Cortex-M0 Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 211
Version 1.1
1
1
1
8
8
8
EXTERNAL BUS INTERFACE (EBI)
18.1 OVERVIEW
The external bus interface (EBI) provides access to external parallel interface devices such as SRAM, Flash, and LCD
modules. The interface is memory mapped into the internal address bus of the Cortex-M0. The data and address lines
can be multiplexed to reduce the number of pins required to connect to external devices. The bus read/write timing can
be adjusted to meet the timing specifications of the external devices.
The EBI only supports asynchronous 8 or 16-bit bus interfaces, and translates the internal AHB transactions into the
external device protocol automatically. If the selected external memory is 16 or 8 bits width, then 32-bit wide
transactions on the AHB are auto split into consecutive 16 or 8-bit accesses.
The EBI supports multiplexed and non-multiplexed addressing modes. The non-multiplexed addressing mode can be
operated more efficiently and faster but it requires more pins. The multiplexed addressing modes are slower and require
an external address latch device and a lower number of pins. The functionality of the 16 AD pins depends on what kind
of the multiplexed addressing mode is used. They are used for both address and data in the multiplexed modes.
However, for the non-multiplexed 8-bit address mode, both the address and data uses these 16 AD pins. If more
address bits or data bits are needed, an external latch can be used to support up to 26-bit addresses or 16-bit data in the
multiplexed addressing modes using only the 16 EBI AD pins. Furthermore, independent of the addressing mode, up to
26 non-multiplexed address lines can be enabled on the EBI_A pin connections.
18.2 FEATURES
Programmable interface for various memory types
1.
Asynchronous static random access memory
– SRAM
2.
Read-only memory
– ROM
3.
NOR Flash memory
4.
8-bit or 16-bit parallel bus CPU interface device
Translates AHB transactions into appropriate external device protocol
4 memory bank regions and independent chip select control for each memory bank
Programmable timings to support a wide range of devices
1.
Programmable wait states or external asynchronous ready signal control
2.
Programmable bus turnaround cycles
3.
Programmable output enable and write enable cycles extension for each memory bank
4.
Individual active high or low setting of interface control signal for each memory bank
Automatic translation when AHB transaction width and external memory interface width is different
Supports multiplexed and non-multiplexed address and data line configurations
1.
Up to 26 address lines
2.
Up to 16-bit data bus width
18.3 PIN DESCRIPTION
Pin Name
Type
Description
GPIO Configuration
AD[15:0]
I/O
Addresses & Data
A[25:0]
O
Addresses
CS[3:0]
O
Chip select
OE
O
Output enable
Содержание SN32F280 Series
Страница 222: ...SN32F280 Series 32 Bit Cortex M0 Micro Controller SONiX TECHNOLOGY CO LTD Page 222 Version 1 1 A1D16...
Страница 263: ...SN32F280 Series 32 Bit Cortex M0 Micro Controller SONiX TECHNOLOGY CO LTD Page 263 Version 1 1 26 2 LQFP 64 PIN...
Страница 264: ...SN32F280 Series 32 Bit Cortex M0 Micro Controller SONiX TECHNOLOGY CO LTD Page 264 Version 1 1 26 3 LQFP 48 PIN...