MEMORY CONTROLLER FOR MEMORY DEVICE
A memory controller that generates interface signals for a memory device determines an interface signal frequency based on a timing mode of the memory device and a corresponding clock division ratio. Based on the timing mode, a look up table (LUT) is selected and then a timing parameter corresponding to the clock division ratio and the interface signal frequency is fetched from the LUT. An interface signal is generated based on the interface signal frequency and fetched timing parameter.
1 . A method for generating an interface signal for a memory device by a memory controller, comprising:
determining an interface signal frequency based on a timing mode of the memory device and corresponding clock division ratio value stored in the memory controller;
selecting a first look-up table (LUT) from a plurality of LUTs stored in the memory controller, based on the timing mode, wherein each LUT stores a mapping between a clock division ratio value and corresponding interface signal frequency and a plurality of timing parameters associated with the interface signal frequency;
fetching at least one timing parameter from the first LUT; and
generating the interface signal based on the interface signal frequency and the at least one timing parameter.
2 . The method of claim 1 , wherein the plurality of timing parameters includes at least one of an address-command, command address delay (tCADf, tCADs), a data output end to write/read (W/R)# high (tCKWR), an access window of DQS from CLK (tDQSD), a W/R# low to DQS/DQ driven by device (tDQSCK), a W/R# high to DQS/DQ tri-state by device (tDQSHZ), a data output cycle to command, an address or data input cycle (tRHW), a ready to data output cycle (tRR), a CLK rising edge to SR[6] low (tWB), a command, address or data input cycle to data output cycle (tWHR), a DQS write preamble (tWPRE), a DQS write postamble (tWPST), a W/R# low to data output cycle (tWRCK), and a WP# transition to command cycle (tWW), active to precharge command (tRAS), ACTIVE to ACTIVE/AUTO REFRESH command period (tRC), AUTO REFRESH command period (tRFC), ACTIVE to READ or WRITE delay (tRCD), PRECHARGE command period (tRP), ACTIVE bank a to ACTIVE bank b command (tRRD), Write recovery time (tWR), REFRESH to REFRESH command interval (tREFC), Access window of DQS from CK/CK# (tDQSCK), Write command to first DQS latching transition (tDQSS), ADV Setup Time (tADVS), ADV Hold Time (tADVH), CS Setup Time to Clock Rising (tCSS), CS Low Hold Time from Clock (tCSLH), CS High Pulse Width (tCSHP), ADV High Pulse Width (tADHP), Chip Select to WAIT Low (tWL), ADV Falling to WAIT Low (tAWL), Clock to WAIT High (tWH), Chip De-select to WAIT High-Z (tWZ), Output Enable to Low-Z Output (tOLZ), Latency Clock Rising Edge to Data Output (tCD), Output Hold (tOH), Burst End Clock to Output High-Z (tHZ), Chip De-select to Output High-Z (tCHZ), Output Disable to Output High-Z (tOHZ), UB, LB Disable to Output High-Z (tBHZ), WE Set-up Time to Command Clock (tWES), WE Hold Time from Command Clock (tWEH), WE High Pulse Width (tWHP), Data Set-up Time to Clock (tDS), and Data Hold Time from Clock (tDHC).
3 . The method of claim 1 , wherein the interface signal includes at least one of a chip enable (CE) signal, a command latch enable (CLE) signal, an address latch enable (ALE) signal, a memory clock signal (CLK), a read/write ready (R/W) signal, a data qualifier strobe (DQS) signal, and a data (DQ) signal.
4 . The method of claim 1 , wherein the memory device comprises at least one of a NAND flash memory, a NOR flash memory, a hard disk drive (HDD), and a double data rate synchronous dynamic random access memory (DDR-SDRAM).
5 . The method of claim 1 , wherein the memory controller comprises at least one of a NAND flash controller, a NOR flash controller, an integrated drive electronics (IDE) controller, a double data rate (DDR) 1 controller, a DDR 2 controller, and a DDR 3 controller.
6 . The method of claim 1 , wherein the clock division ratio value corresponds to a ratio of a system clock frequency to the interface signal frequency.
7 . A memory controller for generating an interface signal for communicating with a memory device, comprising:
a control register for storing a plurality of timing modes of the memory device and a corresponding plurality of clock division ratio values;
a plurality of look up tables (LUTs) connected to the control register, wherein each LUT stores a mapping between a clock division ratio value and corresponding interface signal frequency and a plurality of timing parameters associated with the interface signal frequency;
a multiplexer having a plurality of input terminals connected to a corresponding plurality of the LUTs and a select terminal connected to the control register for receiving a control signal corresponding to the timing mode, wherein the multiplexer selects a first LUT of the plurality of LUTs based on the control signal and outputs at least one timing parameter from the first LUT;
a timing register, connected to an output terminal of the multiplexer, for receiving and storing the at least one timing parameter;
a clock control module, connected to the control register, for generating an interface signal frequency value by dividing a system clock frequency by the clock division ratio value corresponding to the timing mode;
an interface timing controller, connected to the clock control module and the timing register, for receiving the interface signal frequency value and the at least one timing parameter, respectively, and initiating generation of the interface signal; and
an interface signal generator, connected to the interface timing controller, for generating the interface signal.
8 . The memory controller of claim 7 , wherein the plurality of timing parameters includes at least one of an address-command, command address delay (tCADf, tCADs), a data output end to write/read (W/R)# high (tCKWR), an access window of DQS from CLK (tDQSD), a W/R# low to DQS/DQ driven by device (tDQSCK), a W/R# high to DQS/DQ tri-state by device (tDQSHZ), a data output cycle to command, an address or data input cycle (tRHW), a ready to data output cycle (tRR), a CLK rising edge to SR[6] low (tWB), a command, address or data input cycle to data output cycle (tWHR), a DQS write preamble (tWPRE), a DQS write postamble (tWPST), a W/R# low to data output cycle (tWRCK), and a WP# transition to command cycle (tWW), active to precharge command (tRAS), ACTIVE to ACTIVE/AUTO REFRESH command period (tRC), AUTO REFRESH command period (tRFC), ACTIVE to READ or WRITE delay (tRCD), PRECHARGE command period (tRP), ACTIVE bank a to ACTIVE bank b command (tRRD), Write recovery time (tWR), REFRESH to REFRESH command interval (tREFC), Access window of DQS from CK/CK# (tDQSCK), Write command to first DQS latching transition (tDQSS), ADV Setup Time (tADVS), ADV Hold Time (tADVH), CS Setup Time to Clock Rising (tCSS), CS Low Hold Time from Clock (tCSLH), CS High Pulse Width (tCSHP), ADV High Pulse Width (tADHP), Chip Select to WAIT Low (tWL), ADV Falling to WAIT Low (tAWL), Clock to WAIT High (tWH), Chip De-select to WAIT High-Z (tWZ), Output Enable to Low-Z Output (tOLZ), Latency Clock Rising Edge to Data Output (tCD), Output Hold (tOH), Burst End Clock to Output High-Z (tHZ), Chip De-select to Output High-Z (tCHZ), Output Disable to Output High-Z (tOHZ), UB, LB Disable to Output High-Z (tBHZ), WE Set-up Time to Command Clock (tWES), WE Hold Time from Command Clock (tWEH), WE High Pulse Width (tWHP), Data Set-up Time to Clock (tDS), and Data Hold Time from Clock (tDHC).
9 . The memory controller of claim 7 , wherein the interface signal includes at least one of a chip enable (CE) signal, a command latch enable (CLE) signal, an address latch enable (ALE) signal, a memory clock signal, a read/write ready (R/W) signal, a data qualifier strobe (DQS) signal, and a data (DQ) signal.
10 . The memory controller of claim 7 , wherein the memory device comprises at least one of a NAND flash memory, a NOR flash memory, a hard disk drive (HDD), and a double data rate synchronous dynamic random access memory (DDR-SDRAM).
11 . The memory controller of claim 7 , wherein the memory controller comprises at least one of a NAND flash controller, a NOR flash controller, an integrated drive electronics (IDE) controller, a double data rate (DDR) 1 controller, a DDR 2 controller and a DDR 3 controller.
12 . The memory controller of claim 7 , wherein the clock division ratio value corresponds to a ratio of a system clock frequency to the interface signal frequency.
13 . A tangible computer readable medium having a software program including executable instructions that cause a memory controller to generate an interface signal for a memory device, the software program comprising:
determining an interface signal frequency based on a timing mode of the memory device and corresponding clock division ratio value stored in the memory controller;
selecting a first look-up table (LUT) from a plurality of LUTs stored in the memory controller, based on the timing mode, wherein each LUT stores a mapping between a clock division ratio value and corresponding interface signal frequency and a plurality of timing parameters associated with the interface signal frequency;
fetching at least one timing parameter from the first LUT; and
generating the interface signal, based on the interface signal frequency and the at least one timing parameter.
14 . The tangible computer readable medium of claim 13 , wherein the plurality of timing parameters includes at least one of an address-command, command address delay (tCADf, tCADs), a data output end to write/read (W/R)# high (tCKWR), an access window of DQS from CLK (tDQSD), a W/R# low to DQS/DQ driven by device (tDQSCK), a W/R# high to DQS/DQ tri-state by device (tDQSHZ), a data output cycle to command, an address or data input cycle (tRHW), a ready to data output cycle (tRR), a CLK rising edge to SR[6] low (tWB), a command, address or data input cycle to data output cycle (tWHR), a DQS write preamble (tWPRE), a DQS write postamble (tWPST), a W/R# low to data output cycle (tWRCK), and a WP# transition to command cycle (tWW), active to precharge command (tRAS), ACTIVE to ACTIVE/AUTO REFRESH command period (tRC), AUTO REFRESH command period (tRFC), ACTIVE to READ or WRITE delay (tRCD), PRECHARGE command period (tRP), ACTIVE bank a to ACTIVE bank b command (tRRD), Write recovery time (tWR), REFRESH to REFRESH command interval (tREFC), Access window of DQS from CK/CK# (tDQSCK), Write command to first DQS latching transition (tDQSS), ADV Setup Time (tADVS), ADV Hold Time (tADVH), CS Setup Time to Clock Rising (tCSS), CS Low Hold Time from Clock (tCSLH), CS High Pulse Width (tCSHP), ADV High Pulse Width (tADHP), Chip Select to WAIT Low (tWL), ADV Falling to WAIT Low (tAWL), Clock to WAIT High (tWH), Chip De-select to WAIT High-Z (tWZ), Output Enable to Low-Z Output (tOLZ), Latency Clock Rising Edge to Data Output (tCD), Output Hold (tOH), Burst End Clock to Output High-Z (tHZ), Chip De-select to Output High-Z (tCHZ), Output Disable to Output High-Z (tOHZ), UB, LB Disable to Output High-Z (tBHZ), WE Set-up Time to Command Clock (tWES), WE Hold Time from Command Clock (tWEH), WE High Pulse Width (tWHP), Data Set-up Time to Clock (tDS), and Data Hold Time from Clock (tDHC).
15 . The tangible computer readable medium of claim 13 , wherein the interface signal includes at least one of a chip enable (CE) signal, a command latch enable (CLE) signal, an address latch enable (ALE) signal, a memory clock signal, a read/write ready (R/W) signal, a data qualifier strobe (DQS) signal, and a data (DQ) signal.
16 . The tangible computer readable medium of claim 13 , wherein the memory device comprises at least one of a NAND flash memory, a NOR flash memory, a hard disk drive (HDD), and a double data rate synchronous dynamic random access memory (DDR-SDRAM).
17 . The tangible computer readable medium of claim 13 , wherein the memory controller comprises at least one of a NAND flash controller, a synchronous NOR flash controller, an integrated drive electronics (IDE) controller, a double data rate (DDR) 1 controller, a DDR 2 controller, and a DDR 3 controller.
18 . The tangible computer readable medium of claim 13 , wherein the clock division ratio value corresponds to a ratio of a system clock frequency to the interface signal frequency.